
Class l,'BlQ(o\. 
Book 



Wio- 






elume XXI f^yciiological review publications ^«'« No.91 
'^""^ JULY, 1916 



Psychological Monographs 



EDITED BY 
JAMES ROWLAND ANGELL, University of Chicago 
HOWARD C. WARREN, Princeton University {Revietv) 

JOHN B. WATSON, Johns Hopkins University (/. of Exp. Psych.) 

SHEPHERD I. FRANZ, Govt. Hosp. for Insane (Bulletin) and 

MADISON BENTLEY, University of Illinois (Index) 



Acquisition of Skill 

By 
WILLIAM HOWARD BATSON 



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Volume XXI psychological review publications ^!f"l^ ^^- ^^ 
No. 3 JULY, 1916 

Psychological Monographs 



EDITED BY 
JAMES ROWLAND ANGELL, University of Chicago 
HOWARD C. WARREN, Princeton University {Review) 

JOHN B. WATSON, Johns Hopkins University (/. of Exp. Psych.) 

SHEPHERD I. FRANZ, Govt. Hosp. for Insane (Bulletin) and 

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Acquisition of Skill 

By 
WILLIAM HOWARD BATSON 



PSYCHOLOGICAL REVIEW COMPANY 

PRINCETON, N. J. 

AND LANCASTER, PA. 

Agents: G. E. STECHERT & CO., London (2 Star Yard, Carey St., W. C; , 
Leipzig (Koenig Str., 37); Paris (16, Rue de Cond6) 



By Traneter 



is 



y 

•A' 



^-'^^^^ 




ACKNOWLEDGMENTS 

In the first place the writer wishes to express his thanks to 
Prof. John F. Shepard for his many suggestions in planning the 
experiments as well as for valuable assistance in the preparation 
of the manuscript. Thanks are also due to those who acted as 
subjects, — J. E. DeCamp, C. P. Wang, H. Foulk, F. C. Dock- 
eray, E. L. Cole, A. Martin, Roy Feemster, Viola Coldwell, Ro- 
berta Scott and B. A. Hayes, whose services in the experiments 
are very inadequately repaid by these acknowledgments. 



TABLE OF CONTENTS 

PAGE 

Introduction i 

Review of Literature i 

Problem Stated 13 

The Effect of a Number of Factors Working Simul- 
taneously 14 

The Plotting of the Curves 30 

Discussion of Curves 31 

Discussion of Results 34 

The Effect of an Isolated Factor 39 

Experiment I — On Direction 40 

Experiment II — On Force 49 

Experiment III — On Time 58 

The Effect of Several Factors Working in Succession 64 

General Discussion 75 

Long Period Plateaus 75 

Daily Fluctuations 79 

General Form of the Curves 81 

Influence of Objective and Subjective Factors 85 

Warming up Process 86 

The effect of Short and Long Rest Periods 86 

Summary 89 

Bibliography 91 

Curves and Plates 92 



INTRODUCTION 

Review of Literature 

The acquisition of skill in any line of endeavor presents many 
interesting and important problems. In recent years several 
studies have been made to determine the factors that influence 
learning in various fields. 

One of the first experiments carefully worked out upon this 
subject was the study of learning of telegraphy by Bryan and 
Harter.^ Their work was based upon the information gained 
by questioning about two hundred operators, upon reports from 
schools of telegraphy, and upon the records of individuals that 
were studying the subject. Two of these individuals were tested 
weekly from the time they began to practice until they had at- 
tained a fair degree of ability as operators. With a third person, 
the tests commenced about six weeks after he had begun the 
practice. He was tested weekly on his ability to receive, first, 
letters not making words; second, letters making words but the 
words not making sentences; third, letters making words and 
the words making sentences. 

The curves for the first two subjects were plotted by letting 
the divisions on the y-axis represent the number of letters per 
minute sent or received and the divisions on the x-axis represent 
the periods between the tests. The curves for the last subject 
were three in number. The divisions on the y-axis for each of 
these represented the number of letters received per minute and 
the divisions on the x-axis represented the practice periods. The 
first of these was the letter curve, the second the word curve, 
and the third the connected discourse curve. 

As a result of the information gained from those acquainted 
with the work and the tests made by the experimenters, they 
concluded that the curves which represent the sending and re- 

^ Bryan, W. L. and Harter, N. "Studies in the Physiology and Psychology 
of the Telegraphic Language." Psy. Rev., vol. 4, pp. 27-53 and vol. 6, pp. 

345-375- 



2 WILLIAM HOWARD BATS ON 

ceiving ability take different forms. The sending curves rise 
rapidly for some time and then gradually approach parallelism 
with the X-axis. The ordinary receiving curve takes a more 
irregular form and shows at least two extended flat places where 
there appears to be little or no progress. This was not true, how- 
ever, in the letter and word receiving curves. Each of these 
had the same general form as the sending curve. 

The reasons given for the difference in the two kinds of curves 
are the seeming complexity of the language, the difference of 
opportunity for practice, the pleasure involved, and the intensity 
of the effort. Bryan and Harter believe that the receiving of 
the message constitutes a very much more complex act than the 
sending of a message. The learner is able to make progress 
more rapidly in controlling a series of quick movements which 
constitute the sending than in distinguishing the sounds that 
represent the dots and dashes and the back click of the instru- 
ment in receiving. 

Besides this, the opportunity for practice in receiving at a 
slow rate is much less than that for sending at a slow rate. There 
is no reason given as to why it should be more pleasant to send 
than to receive. The intensity of the effort is considered to be 
very important. In this connection, they make the following 
statement : "One conclusion seems to stand out from all these 
facts more clearly than any thing else, namely, that in learning 
to interpret the telegraphic language it is intense effort that 
educates."^ 

They take the sending curve to be the typical practice curve, 
and their principal task is to explain the form of the receiving 
curve. The first ascent appears because the learning of the let- 
ters is comparatively easy. The periods of arrest or plateaus in 
the curve are explained on the basis of different order of habits. 
"A plateau in the curve means that the lower-order habits are 
approaching their maximum development but are not yet suffi- 
ciently automatic to leave the attention free to attack the higher- 
order habits."^ By the lower-order habits are meant those con- 

* Bryan and Harter. Psy. Rev. vol. 4, p. 50. 
^Ibid., vol. 6, p. 357. 



ACQUISITION OF SKILL 3 

cerned with the interpretation of letters, syllables, and words. 
The higher-order habits constitute a system of habits associated 
with groups of words as they are found in connected discourse. 
The plateau is a period when no progress is being made in the 
letter and word habits. They are simply becoming automatic. 
As soon as they are sufficiently brought under control so that 
attention is free, the higher connected discourse habits begin 
to grow and this marks the rise from the plateau. 

The attention at first is confined almost entirely to the letters, 
then to words, and finally to larger sense groups or to the mes- 
sage as a whole. However, the writers do not hold that there is 
complete isolation of the lower and higher habits. "The syn- 
chronous curves of Fig. 30 and the experience of operators agree 
in showing that from an early period letter, word, and higher 
habits make gains (a) simultaneously, but (b) not equally."^ 
The chief gains, however, are in the lower-order habits. In the 
sending curve the various order habits are formed simultan- 
eously and so no plateaus appear. Objective and subjective fac- 
tors have a great influence on the beginner but do not disturb 
the expert. 

Swift studied types of learning of different degrees of com- 
plexity and reached conclusions somewhat at variance with those 
given above.^ For the purpose of studying the improvement 
in what he took to be the simplest type of learning, he had six 
subjects toss balls. Five of these subjects practiced with two 
balls, receiving and throwing one while the other was in the air. 
The other subject practiced with three balls, using both hands 
and keeping one ball always in the air. The balls that he used 
were of solid rubber, weighing 122.6 and 130.2 grams and being 
42 and 44 mm. in diameter respectively. The practice consisted 
of ten trials daily. The number of throws the subject could 
make without missing one of the balls constituted a trial. The 
score for the day was the sum of the catches that were made in 
the ten trials. 

* Bryan and Harter. Psy. Rev. vol. 6, p. 350. 

° Swift, E. J. "Studies in the Psychology and Physiology of Learning." 
Amer. Jour, of Psy. vol. 14, pp. 201-251. 



4 WILLIAM HOWARD BATS ON 

_He found that various objective and subjective factors had a 
very marked effect upon the learning. The physical efficiency 
was very important but the subject could not always tell in ad- 
vance how well he would succeed. He agrees with Bryan and 
Harter that all advance requires effort but further states that 
excessive effort may cause the subject to lose rather than gain 
ability. 

The curves for this work were plotted by taking the divisions 
on the y-axis to represent the number of catches for each daily 
practice and the divisions on the x-axis to represent the practice 
periods. All of the curves for this work have the same general 
form and are concave to the y-axis. All of the curves show great 
irregularity of advance. In these curves there are no long period 
fluctuations, as was noted above. There were, however, several 
short periods during which there was little or no advance. 

No immediate rapid rise appears in these curves as appeared 
in those for telegraphy obtained by Bryan and Harter. Swift 
thinks that this first rapid rise will appear only in those cases 
where symbols or other devices are used for handling and pre- 
senting ideas. He seems to imply that the curve that is concave 
to the y-axis is the normal practice curve.^ 

Swift seems to think that the shorter plateaus that he found 
in this work may be caused by a combination of different factors 
or by a number of factors that act separately. He is not clear 
as to whether there is no progress or whether the progress is such 
that it can not be measured. He says: "This lack of energy, 
due to waning interest, probably has more to do with delaying 
the learner's progress and making plateaus than any thing else. 
One cannot escape a dead level in uninteresting work and after 
the enthusiasm that novelty stirs has spent itself the interest is 
dulled and effort slackens. Yet the slow progress is often only 
an apparent one and due to our inability to measure the ad- 
vance."'^ In support of this last view, he points out that during 
the slow period the subjects occasionally made high scores and 
that at the end of the plateau there was a rise much above the 

' Swift. Amer. Jour, of Psy. v. 14, p. 228. 
^ Swift. Amer. Jour, of Psy. vol. 14, p. 213. 



ACQUISITION OF SKILL 5 

level immediately preceding the plateau. In another place, he 
points out that the delay may be the result of having reached the 
limit of a certain method.^ 

In order to get a curve for a more mental type of work and 
one that would serve as a comparison curve with those obtained 
by Bryan and Harter for telegraphy, Swift studied the learning 
of shorthand.^ He acted as subject himself and was the only one 
tested. In this work, an hour and a half a day was given to 
study for a period of something over ten weeks. During the 
early part of this time the practice was confined to writing the 
material in shorthand, but later the daily periods were divided 
between writing and reading what had been written. He was 
given a ten minute test daily by an assistant. In both the read- 
ing and writing tests the number of words read or written formed 
the basis for the score. The material for the reading tests was 
the matter that he had written ten days before. 

The curve was plotted by letting the divisions on the y-axis 
represent the number of words and the divisions on the x-axis 
represent the practice periods. Swift decided in this work that 
there was no evidence of higher-order habits being separated 
from the lower-order habits. There were no long period 
plateaus. Whatever arrests there were, could be accounted for 
on the ground of emotional factors. 

In explaining the short period plateaus, he uses the following 
language : "In learning shorthand and presumably also in learn- 
ing to receive or send telegraphy, a large number of associations 
are formed that do not affect the speed of the work, because there 
is no opportunity to use them, and the learner seems to make lit- 
tle or no progress, not because this is the particular time for the 
formation of a 'hierarchy of habits', for this is going on all the 
time, but because the range of associated knowledge in the sub- 
ject is too limited to meet the demand."^^ Swift seems to place 
his explanation more on a quantitative than a qualitative basis. 
A certain amount of material must be accumulated and properly 
associated before it becomes effective, and the accumulation of 

* Ihid., p. 214. 

* Ibid., p. 224. 

" Swift Amer. Jour, of Psy. vol. 14, p. 224. 



6 WILLIAM HOWARD BATSON 

this definite quantity of material explains what takes place dur- 
ing the arrest period. 

In his study of typewriting/^ he practiced one hour per day 
with the sight method for forty-four practice days. The score 
was kept by noting the number of words written per hour. The 
curves for the work were plotted by letting the divisions on the 
y-axis represent the number of words per hour and the divisions 
on the X-axis represent the number of practice periods. 

Swift and Schuyler^^ later carried on another experiment on 
typewriting. In this experiment, Schuyler was the subject and 
practiced thirty minutes daily by the touch system. The work 
extended over sixty-six practice days. The material copied was 
at first taken from Grant's typewriting manual, and later lec- 
tures and essays were copied. In this work the number of strokes 
were used as a basis for keeping the score. For a few practice 
periods the same sentence was repeated for the whole half hour. 

In both of these curves the progress was irregular. The change 
of copy, physical condition, subjective state, and perhaps other 
factors contributed to this irregularity. There were no long 
period plateaus as in the curve for telegraphy. Both simple and 
complex factors reveal themselves to introspection from the be- 
ginning of the work. However, the simpler elements are more 
active in the early period. The shorter plateaus such as are found 
here have two causes. "Considered from the standpoint of auto- 
matization, they are resting places. The learner has overshot his 
permanent power and must wait until automatization is per- 
fected. They are also due to slump in enthusiasm."^^ The steps 
of improvement here as in the ball tossing were made uncon- 
sciously and then adopted. Swift holds that this unconscious 
advance is an argument for the idea that the associations are 
being made automatic during the apparent rest periods. The 
lapse of attention which accompanies these plateau periods is a 
result of the accumulation of loosely connected associations. 

"Swift. "The Acquisition of Skill in Typewriting." Psy. Bui. vol. i, pp. 
295-305. 

"^ Swift and Schuyler. "The Learning Process." Psy. Bui. vol. 4, pp. 
307-310. 

"Swift. Psy. Bui. vol. i, p. 305, 



ACQUISITION OF SKILL 7 

In the study of telegraphy, a Morse instrument was used and 
James' "Talks to Teachers" furnished the material. The prac- 
tice consisted of four hours on four successive days given to the 
study of the alphabet and following this were thirty-nine practice 
days. Each of these practice periods consisted of a half hour 
of practice and five minutes test. The curve for this work was 
of the same general form as for ball-tossing and for typewriting. 
He holds that the delays are the result of the time it takes the 
associations to become automatic.^* 

Swift also studied the learning of a language and secured a 
curve for the improvement. The Russian language was used as 
the basis for this work because the subject would be least assisted 
by his past experience. The practice continued from March 30 
until June 14, 1905, and consisted of thirty minutes study and 
fifteen minutes reading each day. The number of words read 
was made the basis for the score. The curve obtained from this 
work showed three periods of advance and four plateaus. He 
holds here that the plateaus do not represent places of no prog- 
ress but that the progress cannot be measured. The lower-order 
and the higher-order habits go along together. ^^ 

Swift has also studied the problem of relearning in ball-tossing 
and typewriting. In both cases, he finds that during a long rest 
period there is little, if any, loss of skill and that the subject in 
a very short time is able to go beyond his best previous record. ^^ 

Book has made a more elaborate study of learning to type- 
write. His aim was to obtain learning curves that might be ex- 
plained in detail by the aid of introspections of the subjects. 
Eleven subjects took part in the work. Both the sight and touch 
methods were used. The score was kept in terms of strokes. 
The curves were plotted by having the divisions on the y-axis 
represent the number of strokes and the divisions on the x-axis 
represent the practice periods. 

"Swift. "Learning to Telegraph." Psy. Bui. vol. 7, pp. I47-IS3. 

"Swift. "Beginning a Language; A Contribution to the Psychology of 
Learning." Studies of Philosophy and Psychology 'by Former Students of 
'Charles Edward Garman. Pp. 297-313. 

"Swift. "Memory of a Complex Skillful Act." Amer. Jour, of Psy., 
vol. 16, pp. 131-133. "Memory of Skillful Movements." Psy. Bui., vol. 3, 
pp. 185-187. "Relearning a Skillful Act." Psy. Bui., vol. 7, i47-iS3. 



8- WILLIAM HOWARD BATSON 

He found that the curves obtained showed three types of 
fluctuations : the first was the short fluctuation from day to day ; 
then there were slightly longer periods of arrest which he called 
"breathing places" ; lastly, there were long periods during which 
there was practically no progress at all, which he called plateaus. 

The daily fluctuations he explained on the basis of objective 
and subjective factors. The principal objective factor was the 
difference in the material to be copied. On the subjective side 
the amount of re-learning and warming up, fluctuations in at- 
tention, and changes in emotional attitude were very important 
factors in determining the daily fluctuations. Fatigue from 
general causes was another important element. 

The breathing places were largely the result of lapses in spon- 
taneous attention. In some cases strong application of voluntary 
effort caused them. Sometimes the subject on good days m.ade 
an unusually high score and for several days it took all his at- 
tention to maintain this level. In this case Book's statement 
that "It takes some time for the new way of writing to become 
sufficiently automatic to allow part of the attention to forge 
ahead in quest of more economic methods,"^"^ seems almost to 
agree with the interpretation of Swift who speaks of giving the 
associations time to become automatized. 

Besides these short period arrests, some long period arrests 
were noted. The curves of two of the subjects, one that had used 
the sight method and the other the touch method, showed pro- 
nounced long period plateaus. Both of these curves extended 
over long periods of time. Book thinks that these plateaus be- 
long to rather definite levels of attainment. There is no regular 
order for the development of special habits in typewriting. These 
long period plateaus "do not represent periods of incubation, 
where certain elementary habits make substantial gains, pre- 
paratory to their organization into higher-order habits, they 
are: (a) Resting places in the learner's interest and effort; or 
(b) 'breakdown' stages caused by excessive effort wrongly ap- 

"Book, W. F. "The Psychology of Skill: with Special Reference to Its 
Acquisition in Typewriting." University of Montana Publications in Psy- 
chology : Bui. No. S3, p. 155- 



ACQUISITION OF SKILL g 

plied."^^ Here Book disagrees with both Swift, and Bryan and 
Harter. 

The rise from the plateau, instead of being the result of old 
associations which have become automatic, is the result of re- I 
newed effort by means of which new short cuts have been dis- / 
covered. He holds that in simple forms of work where only I 
one or a few simple associations are to be formed no plateau j 
hwill appear. Even in cases of complex work, it is possible so to J 
\ direct and control effort that they will not appear. f'Some ol his 
subjects were able to do this complicated work in typewriting 
without the occurrence of any plateau. 

In regard to the warming up and re-learning, the evidence is 
quite conclusive. The records showed that the last half of the 
practice period in almost every case gave better results than the 
first half. Besides the daily revival of the associations already 
learned, there is a process of getting into a certain "set" which 
he terms a "typewriting psychosis," and as this "set" comes 
many of the former difficulties disappear. 

Book also gave a number of memory tests in this work. He 
found that after a period of six months from the time of the 
last regular practice, ten daily tests showed an average slightly 
lower than the last ten tests of the regular practice. One year 
later a second series of ten tests showed a gain over the last 
ten regular practice tests in the number of strokes, but a slightly 
higher percent of errors. Book feels that the increase in the 
number of errors for the memory tests shows that more effort 
was put forth than had been in the regular practice. This, how- 
ever, does not account for the increase of skill in the second 
memory test over the first one nor does it fully explain the gain 
made over the regular practice. The author attributes that gain, 
"to the disappearance, with the lapse of time, of numerous as- 
sociations, bad habits of attention, incidentally acquired in the 
course of learning, interfering habits and tendencies, which, as 
they faded, left the more firmly established typewriting associa- 
tions free to act."^^ 



""Book. "The Psychology of Skill," p. 157. 
" Book. "The Psychology of Skill," p. 80. 



10 WILLIAM HOWARD BATS ON 

Several less extensive studies have been made touching upon 
the subject of the acquisition of skill. Among these may be 
mentioned the work of Scripture, Smith and Brown; Johnson; 
Partridge; Bair; Wells; Starch; and Whitley. 

Scripture, Smith and Brown studied the effect of practice upon 
one's ability to insert a needle into a small hole. They reached 
the conclusion that the improvement was due to the training of 
attention and that it was psychical rather than physical. Any 
distraction or mental or physical fatigue lowered the result. The 
best results were obtained when the attention was fixed upon the 
hole rather than upon the needle."*^ 

Johnson had his subjects practice at tapping at the corners of 
an equilateral triangle. In this work, he found that all of the 
curves of improvement follow the same form. He reached the 
conclusion that transition from a state requiring constant atten- 
tion to a state of automatic control follows a law as exact as 
any physical law. But because the subjects are never mentally 
and physically equal at two different tests and because we do 
not have scientific results from allied subjects, it is difficult to 
determine the law. The closer the personal factors are to the 
normal and the more accurate the measurements, the nearer the 
curve will show the law of habit. The daily variations in the 
curve can be explained by the variations in the subjects.^^ 

Partridge studied the reflex wink. The work consisted of 
having a little hammer hit a glass plate immediately before the 
eye. The two adult subjects used were able to improve greatly 
their ability to inhibit the wink and their curve of improvement 
shows a steady rise from the beginning with the usual daily 
fluctuations in the successive tests. ^^ 

Bair studied the acquisition of control over a voluntary muscle 
and found that the power was gained by associating the given 
muscle in a group with others. After the power was gained to 

^ Scripture, E. W., Smith, T. L., and Brown, E. M. "On the Education of 
Muscular Control and Power." Studies from the Yale Psy. Lab., vol. 2, 
pp. 114-119. 

^Johnson, W. S. "Researches in Practice and Habit." Studies from the 
Yale Psy. Lab., vol. 6, pp. 51-103. 

^Partridge, G. E. "Experiments upon the Control of the Reflex Wink." 
Amer. Jour, of Psy., vol. 11, pp. 244-250. 



ACQUISITION OF SKILL ii 

move it with others, the abihty to move it separately was obtained 
by concentrating the attention upon the particular act. He also 
studied the nature of the improvement of subjects practicing on 
throwing shot into a tumbler and manipulating a modified form 
of typewriter. These tests were continued only for a few days 
and do not give much idea of the curve of improvement.^^ 

Wells did some work with special reference to fatigue phe- 
nomena but also touching upon the problem of improvement. 
The unit of measurement used was the taps upon a telegraph 
key. The subject selected his own method of tapping but did 
not change it during the experiment. The subject commenced at 
a given signal and continued at maximum speed for thirty sec- 
onds. After a rest of two and one half minutes this was re- 
peated. Five trials of thirty seconds each were given each day. 
Two of the subjects practiced for thirty days. The work of these 
two subjects is the only part that is important here. 

The curves show a constant improvement until near the end, 
when progress gradually diminishes. There is no rapid rise at 
the beginning of the curve. In a later test on one of the subjects 
there was an improvement over the best score at the end of the 
practice. 

There was evidence of warming up for both subjects, and as 
the practice continued this warming up process increased. After 
an intermission there was a loss in the right hand in all cases and 
a loss in the left hand in the first case but a gain in the second 
and third for Subject i. Subject ii in all three cases with each 
hand showed a gain. With both subjects, the first interval of 
five seconds showed a gain but fatigue came in and made the 
total score lower in the cases stated above. The only explana- 
tion he offers for the initial increase is that it is the result of a 
renewed "Neuigkeitsantrieb" but he seems to think that the 
practiced co-ordination parts become more firmly set during a 
period of rest. He further points out that the daily fluctuations 
in this work vary more after a week than at the beginning.^^ 

^Bair, J. H. "Development of Voluntary Control." Psy. Rev., vol. 8, pp. 
474-510. "The Practice Curve." Mon. Sup. to Psy. Rev. No. 19. 

^ Wells, F. L. '^Normal Performance in the Tapping Tests." Amer. 
Jour, of Psy., vol. 19, pp. 437-483- 



12 WILLIAM HOWARD BATSON 

Starch studied the trial and error method by having a subject 
trace a six pointed star as it is seen in a mirror. He finds that 
the advantages of using a figure in the form of a star rather 
than some other form are, that it gives frequent changes in di- 
rection, the divisions are of equal length, and they are sufficiently 
long to be difficult and yet not cause undue fatigue. The curves 
were obtained by taking one hundred records made at the rate of 
one a day on consecutive days. Both an error and a time curve 
were plotted. 

The error curve falls rapidly at first and then gradually until 
near the end of the practice where it seems to have reached a 
dead level. The time curve shows a rapid fall at first but after 
about fifty practices it remains nearly parallel to the horizontal 
axis until the error curve ceases to fall then it takes another 
drop. Near the end of the practice it again approaches parallel- 
ism with the x-axis.^^ 

Whitley gave a number of tests to determine individual dif- 
ferences. She emphasizes the importance of a number of tests in 
order to get a true estimate of a person along any line. She 
also points out the danger of mis-interpreting measurements. 
She believes that in the same field, improvement follows the same 
law for different individuals. The higher mental functions are 
more susceptible to practice than the sensory functions. ^^ 

A large number of other improvement tests have been made, 
but, since very little of the motor element was involved, they 
have little connection with this problem and are not discussed. 
In all the tests mentioned except the first three the period of 
practice was rather short and very little can be said about the 
longer period plateaus. In every case the short fluctuations ap- 
peared. 

"* Starch, D. "A Demonstration of the Trial and Error Method of Learn- 
ing." Psy. Bui., vol. 7, pp. 20-23. 

"Whitley, M. T. "An Empirical Study of Certain Tests for Individual 
I>ifferences." Archives of Psychology, No. 19. 



ACQUISITION OF SKILL 13 

Problem Stated 

From this work have grown a number of interesting problems 
and not a few conflicting opinions are held in regard to the 
questions raised. The influence of the objective and subjective 
factors on different types of learning and on the same type of 
learning at different stages of development, the daily fluctuations 
in the curve, the warming up process, the general form of the 
curve, the effect of short and long rest periods — all present fields 
for further study. One of the most troublesome problems is that 
of the plateaus. Are they the result of different habit levels, are 
they due to the automatization of associations, are they depend- 
ent upon attention, or may there be some other explanation ? Are 
they necessary for all or any types of learning? 

The purpose of this study is : first, to get more information in 
answer to the questions stated above; second, to gain such in- 
formation on the other points pertaining to the curve of learning 
as the data will afford. 

The plan of the work has been so to devise experiments that 
the elements determining the curve of learning can be analysed. 
In the first set of experiments, the factors affect the process of 
the learning simultaneously. In the second set, the work is 
reduced to its simplest form and only a relatively simple sensori- 
motor reaction is required. In the third set, several factors in- 
fluence the same learning process but they act in succession. On 
the basis of this work, the curves are plotted and the explanation 
of their form is given. The study ends with a general discussion 
of these results in their relation to the results that have been ob- 
tained in other experimental work in this field. 



THE EFFECT OF A NUMBER OF FACTORS WORKING 
SIMULTANEOUSLY 

Method of Procedure and Results 

This part of the work is a continuation of Swift's ball-tossing 
experiments. The only apparatus used was two hollow rubber 
balls and two pieces of hard rubber. The balls weighed 16.7 
and 1 7. 1 grams and were 1.6 inches in diameter. The pieces of 
hard rubber were cylindrical in form, weighing 8.91 and 8.94 
grams and being .5 inches in diameter and 2.1 inches long. 
Neither the difference in weight of the pieces of hard rubber nor 
of the balls could be noticed. 

Five subjects took part in the work. Subjects D( Decamp), 
B(Batson), W(Wang), and F(Foulk) were all graduate stu- 
dents taking research work in Psychology. Subject H (Hayes) 
was a junior in college taking Psychology. 

Experiment I. Subject D. 

Subject D. was instructed simply to toss and catch the ball so 
that one ball would be always in the air. He had had no previous 
experience. The right hand was used. The practice consisted 
of ten trials daily at 10 A. M. The work was commenced on 
October 8, 1912 and continued until November 23, 1912. After 
the first three days the same room was used for practice. The 
subject knew his score daily as well as that of each of the other 
subjects doing the work at that time. There was no limit put 
upon the time between trials. At first scarcely any time was 
taken but as the success became greater and the work was more 
fatiguing a minute or two was taken for rest between successive 
trials. Table I shows the result of this practice in detail. 



ACQUISITION OF SKILL 15 

TABLE I 
Subject — D. 
Experiment — ^Tossing and catching two rubber balls with right hand. 



Trials 


I 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Sum 


Oct. 9 


I 


2 


2 


2 


3 


3 


3 


I 


2 


2 


21 


10 


2 


2 


4 


7 


3 


3 


7 


I 


3 


6 


38 


II 


3 


I 


8 


3 


3 


3 


I 


2 


3 


2 


29 


12 


2 


3 


2 


3 


2 


2 


5 


2 


2 


3 


26 


13 


2 


3 


3 


II 


4 


I 


3 


2 


2 


5 


36 


14 


7 


I 


2 


9 


3 


I 


2 


I 


I 


4 


31 


15 


5 


4 


3 


4 


2 


2 


2 


I 


3 


3 


29 


16 


3 


6 


3 


3 


2 


2 


3 


3 


2 


2 


29 


17 


24 


2 


2 


4 


10 


2 


5 


3 


5 


3 


60 


18 


6 


12 


4 


4 


5 


8 


3 


8 


3 


3 


56 


19 


10 


7 


4 


10 


2 


5 


I 


2 


4 


I 


46 


20 


18 


4 


2 


3 


4 





3 


4 





8 


46 


21 


2 


9 


5 


I 


4 


3 


3 


2 


4 


II 


44 


22 


5 


5 


4 


3 


6 


17 


3 





9 


2 


54 


2?, 


13 


4 


9 


5 


4 


I 


2 


4 


9 


3 


54 


24 


4 





14 


7 


8 


33 





2 


3 


14 


85 


25 


22 


3 


6 





2 


5 


3 


7 


4 


5 


57 


26 


6 


12 


4 


5 


9 


13 


II 


II 


5 


6 


82 


27 


9 


9 


16 


22 





3 


7 


2 


II 


3 


82 


28 


10 


20 


9 


7 


24 


29 


22 


2 


35 


26 


184 


29 


10 


I 


16 


35 


7 


3 


I 


27 


I 


4 


105 


30 


23 


23 


4 


31 


21 


2 


28 


17 


15 


5 


169 


31 


17 


3 


35 


40 


4 


17 


18 


7 


18 


37 


196 


Nov. I 


19 


I 


I 


9 


I 


8 


2 


8 


32 


18 


99 


2 


21 


10 


40 


19 


35 


40 


I 


6 


12 


14 


198 


3 


37 


II 


34 


6 


12 


32 


62 


5 


56 


45 


300 


4 


52 


4 


20 


II 


32 


58 


9 


28 


2 


61 


277 


5 


52 


25 


47 


49 


45 


5 


59 


3 


45 


65 


395 


6 


17 


4 


67 


43 


6 


6 


4 


10 


29 


114 


300 


7 


14 


13 


32 


29 


5 


34 


34 


9 


I 





171 


8 


18 


23 


22 


16 


18 


10 


39 


48 


96 


54 


344 


9 


84 


23 


4 


60 


80 


22 


16 


21 


7 


33 


350 


10 


24 


30 


6 


27 


9 


33 


48 


37 


5 


5 


224 


II 


2 


51 


25 


24 


27 


67 


13 


72 


16 


24 


321 


12 


8 


22 


38 


9 


81 


27 


24 


57 


28 


66 


360 


13 


37 


42 


64 


SI 


88 


8 


64 


18 


60 


31 


471 


14 


42 


15 


21 


26 


37 


64 


102 


77 


30 


24 


438 


15 


57 


5 


39 


29 


27 


23 


16 


62 


76 


12 


346 


16 


100 


2 


22 


35 


46 


3 


43 


42 


17 


60 


380 


17 


48 


55 


27 





48 


10 


3 


9 


30 


5 


235 


18 


22 


25 


lOI 


2,3 


35 


6S 


37 


123 


17 


53 


511 


19 


8 


26 


88 


265^ 


16 


95 


82 


19 


32 


78 


709 


20 


36 


151 


20 


29 


74 


79 


58 


30 


48 


63 


588 


21 


3 


151 


259 





170 


58 


70 


247 


181 


26s 


14CX4 


22 


116 


88 


72 


94 


80 


53 


179 


222 


47 


124 


1075 


23 


113 


30 


137 


178 


65 





74 


352 


96 


24 


1069 



Total 1134 943 ^357 1261 1169 958 1175 1616 1115 1396 12124 

When these trials are divided on the basis of those that fall 
below twenty, those between twenty and ninety, and those that 
are ninety or above, the following results are obtained: 



i6 WILLIAM HOWARD BATS ON 

Below 20 20 to 90 90 or more 

First third of table 149 i o 

Second third of table 98 52 o 

Third third of table 37 99 24 

The horizontal columns opposite the dates show how many 
catches were made each trial. The vertical column to the right 
marked "Sum" shows the number of catches that were made 
during the ten trials of each day's practice. The last set of 
figures at the bottom of each vertical column shows the sum of 
the columns. This gives the sum, of all the first trials, second 
trials, etc. The number at the base of the column marked Sum 
shows the total number of catches that the subject made in all 
the practice that was taken. 

The subject was tested again under the same conditions on 
August 15 and 17, 191 3, and the following figures were obtained: 

Trials 123456789 10 Sum 

Aug. 15 85 90 84 108 89 2,2 97 108 82 107 882 
Aug. 17 113 107 2431 18 88 7^ 148 8 148 54 1005 

He was tested again July 10, 191 4, and made: 

Trials 123456789 10 Sum 

July 10 95 166 297 268 131 253 351 432 75 482 2550 

The balls for this test were similar to those used above but 
weighed 20.3 and 18. i grams respectively. The test was made 
in a smaller room but it is not likely that this had any effect 
upon the throwing. The subject had not practiced from the time 
the regular practice had ended up to the time of the test of 
August 15, 19 1 3. Between that time and the test in July 191 4, 
he had occasionally tossed different objects but was sure that all 
this practice would not amount to a half hour. 

Experiment II. Subject B. 
In this experiment the work was the same as in the preceding 
one, that is to toss and catch two balls. The method was to 
center the attention on some one phase of the work. The sub- 
ject aimed to fix his attention on the manner of pitching the 
balls. The balls were pitched in a circle from right to left. Only 
a very little incidental practice in this work had taken place 



ACQUISITION OF SKILL 17 

before the experiment. The right hand was used. The practice 
was in the forenoon and consisted of ten trials daily. The work 
commenced on October 15, 1912 and continued until November 
II, 1912. All the practice was in the same room. The daily 
score was known. As much time was taken between the separate 
trials as the subject desired. Table Ila shows the result of this 
work. Table Ila is arranged the same as Table I and the ex- 
planation of the first table may be used for this one. 

TABLE Ila 
Subject — B. 

Experiment — Tossing and catching two rubber balls with right hand. 
Trials 123456789 10 Sum 

Oct. IS 7 8 6 6 I 6 4 II 9 17 75 

16 I 10 13 2 2 7 4 4 5 6 54 

17 3 13 7 20 10 23 12 10 10 17 125 

18 12 2 3 I 5, 22 22 o 5 3 75 

19 10 27 2 35 I 15 16 8 8 10 132 

20 12 8 9 30 4 II 24 13 31 35 177 

21 6 I o 32 3 47 24 25 10 28 176 

22 37 7 I 41 35 34 4 23 31 8 221 

23 13 19 2.3 6 49 18 14 36 28 23 229 

24 I 23 2 41 12 4 38 31 22 29 203 

25 II 7 12 28 6 37 23 35 46 14 219 

26 4 6 28 70 45 16 19 52 17 18 275 

27 II 9 25 35 45 24 53 46 24 40 312 

28 34 77 38 7 o 20 II 79 28 70 364 

29 20 40 24 42 64 15 79 69 90 67 510 

30 98 58 52 142 31 52 33 16 6 8 496 

31 7 72 3 IS 31 35 38 35 54 4i 33i 
Nov. I 29 75 69 21 109 48 112 33 77 66 639 

2 44 165 148 92 19 56 108 40 34 59 765 

3 I 63 no 41 13 II 27 34 31 167 498 

4 3 114 24 II 63 22 117 79 60 13 506 

5 25 20 47 23 29 59 75 100 15 184 577 

6 23 19 104 63 123 118 92 42 73 137 793 

7 183 90 31 no 163 153 III 142 64 74 1120 

8 159 107 112 33 26 58 53 95 18 42 703 

9 31 46 124 131 42 39 65 84 74 245 881 
10 114 67 43 46 262 134 149 96 84 197 1 192 
ir 29 206 184 65 179 332 14 7 121 134 1271 

Total 927 1359 1244 1 189 1372 1416 1340 1245 1075 1752 12919 

When the trials of Table Ila are divided on the basis of those 
that fall below twenty, those between twenty and ninety, and 
those ninety or above, the following results are obtained : 

Below 20 20 to 90 90 or more 

First third of table 64 26 o 

Second third of table 27 58 5 

Third third of table 12 47 4i 



i8 WILLIAM HOWARD BATS ON 

After the subject had been able to make an average of one 
hundred catches per trial on successive days with the right hand, 
the practice was changed to the left hand. The method was to 
give attention to all the particulars, — the force of the throws, 
the direction, the manner of catching the ball, the position of the 
body, etc. There had been no previous practice with the left 
hand. The practice consisted of ten trials daily in the forenoon. 
The work commenced November 12, 191 2 and continued until 
January 15, 191 3, with an intermission from December 20 to 
January 8 and one practice period on November 28. A part of 
the practice was in a smaller room than that in which the work 
commenced, but the walls were the same in color and the lighting 
was about the same. The daily score was known. No time limit 
was set between trials. The result of this practice is shown in 
Table lib. 

TABLE ILb 

Subject — B. 

Experiment — Tossing and catching two rubber balls with left hand. 

Trials 123456789 10 Sum 



Nov. 12 


2 


4 


2 


4 





4 


2 


6 


2 


5 


31 


13 


3 


2 


2 


3 


7 


5 


6 


3 


I 


8 


40 


14 


6 


6 


7 


9 


8 


8 


9 


6 


8 


2 


69 


15 


21 


2 


20 


3 


2 


2 


2 





4 


10 


66 


16 


13 


13 


I 


7 


10 


17 





I 


9 


7 


78 


17 


3 


7 


6 


2 


6 


2 


8 


10 


6 





50 


18 


6 


3 


8 


21 


3 


7 


4 


6 


9 


4 


71 


19 


5 


17 


4 


4 


7 


8 


7 


9 


2 


10 


73 


20 


I 


II 


17 


7 


3 


4 


8 


II 


9 


13 


84 


■ 21 


9 


4 


2 


12 


II 


9 





10 


25 


10 


92 


22 


28 


12 


4 


18 


7 


14 


6 


14 


22 


19 


144 


23 


2 


17 


14 


20 


3 


19 


12 


8 


II 


15 


121 


24 


3 


7 


II 


4 


12 


II 


6 


4 


9 


II 


78 


25 


16 


8 


II 


10 


16 


5 


3 


II 


8 


5 


93 


26 


7 


II 


7 


7 





-? 


21 


10 


19 


14 


98 


27 


3 


S 


14 


28 


13 


6 


I 





15 





85 


28 
























29 


2 


10 


6 


5 


14 


21 


IS 


6 


23 


4 


106 


30 


6 


6 


2 


21 


12 


13 


20 


42 


13 


14 


149 


Dec. I 


9 


IS 


28 


12 


20 


22 


2 


20 


8 


27 


163 


2 


22 


14 


8 


12 


13 


IS 


I 


7 


8 


13 


113 


3 


10 


23 


4 


13 


16 


IS 


21 


20 


II 


S 


138 


4 


28 


16 


6 


9 


19 


20 


27 


2 


26 


3 


156 


5 


15 


II 


14 


12 


25 


22 


10 


29 


12 


24 


174 


6 


9 


31 


19 


12 


23 


16 


29 


S 


7 


39 


190 


7 


10 


35 


10 


40 


20 


20 


17 


32 


6 


23 


213 


8 


22 


17 


17 


28 


40 


27 


17 


29 


3 


14 


214 


9 


21 


SO 


8 


49 


5 


21 


26 


41 


13 


7 


241 


10 


31 


40 


35 


34 


S 


24 


37 


II 


26 


5 


248 



ACQUISITION OF SKILL 



19 



TABLE lib 
Subject — B. 

Experiment — Tossing and catching two rubber balls with left hand. 
Trials 123456789 10 Sum 



Dec. 1 1 


5 


6 


36 


39 


17 


30 


46 


21 


II 


45 


255 


12 


26 


56 


II 


4 


8 


27 


24 


9 


24 


52 


241 


13 


19 


71 


3 


53 


63 


23 


7 


21 


36 


41 


337 


14 


74 


90 


34 


30 


5 


7 


60 


7 


I 


39 


347 


15 


60 


18 


8 


32 


140 


83 


29 


39 


59 


83 


551 


16 


3 


5 


63 


178 


80 


38 


3 


104 


45 


96 


61S 


17 


no 


56 


69 


79 


35 


64 


88 


48 


45 


29 


623 


18 


38 


5 


25 


50 


204 





43 


20 


32 


42 


459 


19 


31 


34 


12 


28 


75 


II 


23 


lOI 


46 


74 


435 


20 


35 


91 





I 


21 


22 


27 


14 


35 


6 


252 


Jan. 8 


14 


153 


40 


66 


85 


S 


91 


45 


42 


67 


608 


9 


lOI 


61 


16 


46 


127 


108 


9 


19 


23 


6 


S16 


ID 


58 


103 


62 


31 


44 


41 


10 


95 


51 


16 


511 


II 


83 


37 


S7 


24 


9 


149 


85 


31 


45 


76 


596 


12 


45 


44 


118 


30 


48 


12 


17 


94 


II 


108 


527 


13 


118 


65 


73 


30 


8 


133 


60 


123 


117 


119 


846 


14 


35 


130 


289 


48 


166 


119 


133 


162 


153 


IIS 


1350 


IS 


42 


73 


268 


241 


156 


10 


161 


26 


52 


141 


1 170 



Total 1210 1495 1470 1416 1611 1241 1233 1332 1143 1466 13617 

When these trials of Table lib are divided on the basis of 
those that fall below twenty, those between twenty and ninety, 
and those that are ninety or more, the following results are 
obtained : 



20 


to 
7 

63 
88 


90 


90 


or 



38 


more 



Below 20 

First third of table 143 

Second third of table 87 

Third third of table 34 



The subject was tested again on July 17, 191 4. The condi- 
tions were the same except that the balls were slightly heavier, 
weighing 20.3 and 18.1 grams respectively. The difference in 
weight, however, could not be noticed. 

With the right hand, the following score was made : 
Trials 123456789 10 Sum 

July 17 329 4 7 142 o 86 100 I 227 228 1 124 
July 18 63 82 55 201 130 257 169 60 36 384 1437 

The left hand was tested on July 17, 191 4, and again two days 
later. The score was : 



WILLIAM HOWARD BATSON 



Trials 


I 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Sum 


July 17 
July 19 


10 
23 


17 
70 


57 
59 


73 

52 


14 

88 


78 
46 


41 
68 


98 
130 


52 
114 


49 

52 


492 
702 



The subject had tossed tennis balls a few times after the regu- 
lar practice had stopped but not over fifteen minutes had been 
spent in such work. There had been no practice with the left 
hand. A rest of two minutes was made between each trial of 
this last practice. 

Experiment III. Subject W. 
The subject was instructed to toss and catch the two balls after 
the same manner as the other subjects. The practice consisted 
of ten trials daily at eight A. M. The work was commenced 
Oct. 30, 1912, and continued until Feb. 12, 1913. During this 
time, the following daily practices were missed: Nov. 3, 5, 6, 
21 ; Dec. 7, 8, 12, and the period from Dec. 20 to Jan. 8. After 
a few practices, the subject rested one minute between trials. 
He had had no previous practice in the work. The results of 
his work are shown in Table III. 

TABLE III 
Subject — W. 

Experiment — Tossing and catching two rubber balls with right hand. 
Trials 12 3 456789 10 Sum 

Oct. 30 I I I 4 I 2 3 I 3 3 20 

31 223322 3 422 25 

Nov. 1222223211320 

2413431213224 

3 
4212312341120 

5 

6 

71022335543 28 

8223 1456275 37 

94525367553 45 

10 5 o 5 4 8 3 5 3 6 6 45 

11 0570335326 34 

12 4 14 2 8 2 2 4 2 5 3 46 

13 5 4 3 6 4 3 7 2 I 5 40 

14 6473 II 26624 51 

15 4345246366 43 

16 5 7 18 8 9 3 4 I 8 I 64 

17 5 3 7 o 5 8 2 o 5 I 36 
Nov. 18 2440833 I 2 734 

19 II o 6 7 2 14 2 9 16 9 76 

20 10 6 I 3 2 II 2 9 4 8 56 
21 

22 2 3 4 13 I o 2 7 2 II 45 



ACQUISITION OF SKILL 21 

TABLE III— (Continued) 
Subject — W. 

Experiment — Tossing and catching two rubber balls with right hand. 
Trials 123456789 lo Sum 



23 


3 


15 


17 


4 


3 


7 


5 


12 


13 


2 


81 


24 


4 


2 


5 


9 


8 


7 


9 


12 


8 


IS 


79 


25 


4 


22 


7 


20 


4 


13 


9 


4 


8 


3 


94 


26 


3 


8 


7 


20 


10 


7 


4 


II 


9 


3 


82 


27 


12 


8 


II 


22 


7 


6 


18 


I 


4 


24 


113 


28 


2 


4 


8 


5 


2 


6 


8 


8 


4 


4 


51 


29 


II 


2 


7 


I 


8 


5 


I 








7 


42 


30 


IS 


IS 


4 


II 


26 


9 


12 


4 


17 


5 


118 


Dec. I 


s 


4 


10 


9 


4 


10 


8 


5 


5 


2 


62 


2 


4 


10 


5 


6 


9 


23 


6 


17 


12 


3 


95 


3 


8 


29 


21 


3 


19 


16 


22 


7 


II 


16 


152 


4 


II 


2S 


7 


7 


5 


25 


7 


4 


29 


10 


130 


5 


3 


IS 


28 


32 


17 


5 


16 


24 





12 


152 


6 

7 


I 





7 


II 


II 


52 


2 


6 


12 


12 


114 


8 
9 


I 


9 


2 


9 


24 


24 


16 


8 


19 


17 


129 


10 


29 


20 


34 


10 


32 


7 


10 


52 


31 


5 


230 


II 
12 
13 


5 


17 


8 


17 


21 


25 


S3 


6 


22 


34 


208 


7 


14 


29 


9 


66 


5 


7 


2 


39 





178 


14 


12 


23 


6 


29 


35 


25 


2 


6 


42 


9 


189 


IS 


8 


I 


II 


10 


2 


28 


9 





12 


IS 


96 


16 


23 


14 


29 


13 


39 


13 


40 


28 


14 





213 


17 


3 


12 


16 


31 


35 


19 


31 


36 


12 


49 


244 


18 


28 


II 


19 


4 


63 


ID 


6 





24 


13 


178 


19 


33 


12 


29 


81 


21 


23 


26 


43 


13 


62 


343 


20 


96 


S2 


5 


58 


7 


4 


16 


55 


39 


18 


350 


Jan. 8 


12 


10 


II 


25 


SS 


II 


17 


18 


47 • 


32 


238 


9 


21 


8 


23 


80 


19 


8 


23 


44 


II 


18 


25s 


10 


22 


25 


8 


49 


40 


8 


21 


4 


IS 


84 


276 


II 


10 


66 


5 


12 


10 


8 


17 


17 


4 





149 


12 


8 


35 


40 


63 


3 


7 


II 


8 


22 


SO 


247 


13 


30 


S2 


56 


50 


13 


62 


34 


63 





I 


361 


14 


32 


30 


III 


39 


80 


42 


13 


21 


23 


28 


419 


15 





S9 


27 


20 


55 


30 


24 


13 


24 


24 


276 


16 


8 


84 


36 


24 


3 


16 


27 


33 


32 


31 


294 


17 


10 


7 


13 


87 


24 


37 


24 


58 


19 


68 


347 


18 


II 


24 


16 


41 


12 


28 


50 


23 


32 


6 


243 


^9 


28 


36 


26 


23 


19 


39 


23 


51 


40 


26 


311 


20 


26 


27 


25 


46 


13 


18 


45 


14 


25 


10 


249 


21 


8 


32 


10 


18 


56 


II 


19 


32 


26 


66 


278 


22 


24 


SI 


SS 


25 


27 


10 


14 


50 


16 


10 


282 


23 


3 


19 


3S 


SO 


55 


91 


20 


75 


33 


42 


423 


24 


23 


79 


IS 


78 


60 


IS 


3 


13 


6 


22 


314 


25 


4 


26 


22 


38 


28 


24 


27 


73 


30 


SO 


322 


26 


3 


74 


64 


32 


63 


SO 


39 


38 


'68 


17 


448 


27 


9 


41 


33 


28 


62 


67 


20 


43 


38 


4 


342 


28 


21 


7 


8 


9 


no 


74 


54 


124 


9 


SO 


466 


29 


61 


93 


95 


60 


7 


17 


36 


I 


9 


18 


397 


30 


19 


10 


27 


15 


S3 


21 


20 


15 


57 


SO 


287 








Second trial on 


same 


day 










30 


27 


19 


39 


23 


43 


14 


49 


27 


40 


30 


311 


31 


S4 


69 


33 


97 


29 


66 


33 


25 


13 


43 


462 


Feb. I 


32 


30 


II 


2 


16 


46 


28 


48 


89 


37 


339 


2 


87 


36 


S 


23 


68 


72 


12 


20 


26 


22 


371 



22 WILLIAM HOWARD BATSON 

TABLE III— {Continued) 
Subject — W. 

Experiment — Tossing and catching two rubber balls with right hand. 
Trials 123456789 lo Sum 

Feb. 3 43 51 62 14 8 37 36 25 48 88 412 

4 3 29 89 22 64 105 26 79 90 41 558 

5 19 51 9 32 loi 50 29 41 126 27 485 

6 so 9 S3 97 54 58 91 I33 127 26 698 

7 4 41 43 3 83 II 52 84 79 127 537 

8 26 24 105 2,7 iZ 79 81 133 16 48 582 

9 72 136 106 27 186 61 12 52 72, 16 741 

10 67 9 106 100 44 71 114 III 70 152 844 

11 19 77 118 160 159 172 88 66 22 117 999 

12 181 no 132 59 72 103 178 116 2,(> 118 iios 

Total 1485 1997 2090 2120 2381 2093 1842 221 1 1923 2038 20180 

When the trials of Table III are divided on the basis of those 
that fall below twenty, those between twenty and ninety and 
those ninety or above, the following results are obtained : 

Below 20 20 to 90 90 or more 

First third of table 265 5 o 

Second third of table 158 no 2 

Third third of table 68 176 36 

Subject W. was tested again under the same conditions on 
June 26 and 27, 191 3. He had had no practice in the meantime. 
The results were: 

Trials 123456789 10 Sum 

June 26 2 62 27 68 73 27 167 92 66 116 712 

June 27 53 51 173 230 36 170 67 130 181 215 1306 

On July 3, 1 914, the subject was tested again in the same 
room and under the same conditions except that the balls weighed 
20.3 and 18. 1 grams respectively. The scores were: 

Trials 123456789 10 Sum 

July 3 146 55 116 115 105 118 201 205 156 14s 1362 

The subject had thrown a few times three or four months 

before with tennis balls but with no intention of making a high 

score. He had also tested himself once before with these same 

balls but did not think that over twenty minutes had been spent 

in such practice. 

Experiment IV. Subject F. 

Part I 

In the first part of this experiment, the subject was to toss 

and catch the two pieces of hard rubber described above in the 

same manner as the other subjects caught the balls. No specific 

directions in regard to the manner of attending the work were 



ACQUISITION OF SKILL 23 

given. The subject had had some httle experience in tossing and 
catching balls. The right hand was used. The practice con- 
sisted of ten trials. The work was commenced on Oct. 9, 1912 
and continued until Jan. 12, 191 3. The practice was on alter- 
nate days from Oct. 9 to Nov. 19 and after that it was daily. 
The following practices were missed : Nov. 24 and from Dec. 
20 to Jan. 8. The same room was used for all the work except 
a few practice periods near the end. The last room was not very 
different from the former one and no change was noted as a 
result of this. The subject knew his score. He took as much 
rest between trials as he desired but it was never over two or 
three minutes. The results of his work are shown in Table IV 
which is arranged on the same plan as those for the ball tossing. 

TABI'E IV 
Subject — F. 

Experiment — Tossing and catching two pieces of hard rubber. 
Trials 123456789 10 Sum 



Oct. 9 


2 


7 


9 


8 


12 





6 


9 


7 


6 


68 


II 


I 


4 


6 


5 


2 


8 


II 


10 


9 


9 


65 


13 

15 
17 


3 

2 
I 


3 
2 

5 


9 
3 
8 


19 
6 

3 


5 
10 

7 


9 
13 
26 


7 
6 

4 


13 
4 
12 


7 
IS 
13 


3 

5 
18 


78 
66 
97 


19 


17 


3 


14 


14 


9 


II 


7 


6 


3 


32 


116 


21 


17 


2 


ID 


9 


4 


18 


7 


6 


12 


5 


90 


2Z 


II 


14 





6 


3 


8 


15 


12 


II 


9 


89 


25 


2Z 


10 


2 


13 


3 


6 


4 


6 


4 


10 


91 


27 


20 


3 


9 


4 


22 


8 


30 


9 


12 


9 


126 


29 


13 


3 





6 


47 


12 


II 


22 


2 


II 


127 


31 

Nov. 2 


25 
7 


17 
3 


9 

9 


10 

10 


2 

14 


9 

2 


3 

26 


5 
5 


II 

3 


II 

7 


102 
86 


4 


3 


12 


13 


35 


12 


19 


6 


II 


8 


3 


122 


6 


13 


II 


7 


5 


21 


39 


40 


12 


18 


17 


183 


8 


6 


2 


II 


29 


7 


5 


13 


22 





6 


lOI 


10 


17 


8 


4 


16 


3 


2 


15 


14 





9 


88 


12 
14 


7 
5 


24 
6 


II 
9 


7 
17 


10 

12 


5 
57 


15 
7 


20 
64 


7 
6 


52 
6 


158 
189 


16 


24 


9 


25 


15 


37 


12 


I 


47 


32 


56 


258 


18 
19 


9 
18 


13 

28 


3 

21 


18 
17 


14 
16 


4 
53 


7 
28 


39 

17 


41 
12 


4 
14 


152 
224 


20 


5 


21 


10 


7 


9 


26 


39 


12 


8 


4 


141 


21 


7 


IS 





32 


5 


31 


21 


20 


13 


22 


166 


22 


20 


8 


53 


22 


40 


II 


21 


3 


35 


3 


216 


23 


14 


16 





12 


31 


20 


19 


3 


28 


II 


154 


24 

25 


17 


44 


5 


7 


22 


12 


10 


35 


2 


20 


174 


26 

27 
28 


7 

34 

8 


30 

7 

16 


14 
II 
30 


25 

22 

47 


2 
18 

4 


12 
46 
19 


37 
26 

4 


41 
9 
13 


29 

7 
8 


9 

25 
9 


206 

215 
158 


29 


41 


4 


26 


22 


4 


14 


2 


42 


26 


7 


188 



30 3 o 10 24 5 13 14 o I o 70 



24 



WILLIAM HOWARD BATS ON 



.. TABLE IV 
Subject — ^^F. 

Experiment — Tossing and catching two pieces of hard rubber. 

Trials 123456789 lo Sum 

Dec. I 34 2 13 22 75 32 15 4 8 18 223 

2 24 45 5 II 13 8 12 I 36 78 233 

3 13 3 12 34 14 7 9 13 13 S3 171 

4 II 20 o I 16 12 5 6 3 22 96 

5 19 18 3 28 39 36 3 49 44 9 248 

6 20 34 9 37 52 54 44 46 13 26 335 

7 14 15 5 31 II 30 56 95 3 36 296 

8 10 69 35 40 108 59 121 10 8 104 564 

9 15 103 53 67 85 28 no 25 24 22 532 
,10 7 194 193 66 157 128 115 46 53 6 965 

11 121 119 13 133 72 44 103 71 108 57 841 

12 68 34 53 23 141 130 88 146 41 84 808 

13 76 91 91 113 113 122 44 66 32 61 799 

14 36 145 115 12 96 2 38 98 18 64 624 

15 44 165 83 30 no 52 77 24 112 78 775 

16 54 45 19 121 208 71 69 4 179 71 841 

17 66 265 294 195 III 59 30 15 54 197 1286 

18 I 71 102 120 180 II 285 60 77 29 836 

19 91 12 136 16 31 25 159 88 128 33 719 

20 10 115 117 137 76 98 57 5 95 36 746 
Jan. 8 20 37 89 60 I 54 24 19 102 80 486 

9 14 60 41 24 99 35 59 117 77 37 S63 

10 6 113 72 9 159 23 82 67 35 57 623 

11 4 191 318 187 9 no 19 25 39 165 1067 

12 221 484 20 391 78 123 254 109 159 116 1955 

Total 1409 2800 2232 2410 2466 1885 2340 1752 1851 1951 21096 
When the trials in Table IV are divided on the basis of those 
that fall below twenty, those between twenty and ninety, and 
those ninety or more, the following results are obtained : 

Below 20 20 to 90 90 or more 

First third of table 169 21 o 

Second third of table 114 76 o 

Third third of table 31 90 69 

The subject was tested again on June i, 191 3, and made the 

following score : 

Trials 123456789 10 Sum 

June I 29 157 158 69 154 no 10 o 54 21 762 

June 2 4 97 27 31 19 106 75 67 14 184 624 

No practice had been taken between the end of the regular 

practice and this date. 



Experiment IV. Subject F. 

Part II 

In this part of the experiment the subject was requested to 

toss and catch two balls, keeping one in the air all the time. 

The same balls were used that had been used by the other sub- 



ACQUISITION OF SKILL 



25 



jects. The practice was with the left hand. The subject had 
had no previous practice with that hand. In this work, the 
subject continued each day until he had made one thousand 
catches. There was a rest of one minute between each hundred 
catches. The work was commenced on Jan. 13, 19 13 and con- 
tinued daily until Feb. 4, 191 3. 

The number of misses before a hundred catches were made in 
each trial and the total number of misses in each day's practice 
are shown in Table V. Where zero appears in the table, the 
subject was able to make a score of one hundred without missing. 
It should be noted that the number of misses counted is always 
one less than the number of trials for each one hundred catches. 

When the columns are added vertically so as to show how 

many misses were made in catching the first hundreds, second 

hundreds, etc., the following figures were obtained: 

I St 2nd 3rd 4th sth 6th 7th 8th 9th loth Sum 
44 27 32 Z7 38 52 36 26 23 35 350 

The total number of catches was 23000. This represents the 
amount of practice the subject had. Table Va shows this work 
in detail. This table, with the exception of the first day's prac- 
tice, shows where each miss was made for each one hundred 
catches. 

TABLE V 
1st 2nd 3rd 4th 5th 6th 7th Sth 9th loth Sum 



100 



100 100 



Jan. 13 


4 


4 


5 


8 


4 


12 


8 


3 


4 


4 


56 


14 


5 


5 


4 


8 


9 


6 


2 


2 


I 


3 


45 


15 


3 


2 


I 


5 


S 


7 


5 


4 


I 


2 


35 


16 


2 


2 


3 


3 


4 


2 


4 


I 


3 


4 


28 


17 


3 


3 


2 


2 


S 


2 


2 


I 


2 


2 


24 


18 


3 





3 





2 


I 


2 


I 





5 


17 


19 


2 


I 


I 








I 


I 





3 


3 


12 


20 


4 





I 





I 





I 


I 


I 





9 


21 


I 





2 


I 


I 


I 


I 


I 





3 


II 


22 


2 








I 





3 


2 





I 


I 


10 


23 


2 


3 


2 





2 


4 


J. 


3 





2 


19 


24 


2 


I 


2 


4 


I 


4 





I 


2 


I 


18 


25 


2 





I 














2 


3 


I 


9 


26 


2 


I 


I 


I 





I 


2 








I 


9 


27 


I 


I 


I 


I 





3 


I 


2 


I 


I 


12 


28 





2 





I 


I 


I 


I 











6 


29 











I 

















I 


2 


30 





2 


I 


I 





2 





2 


I 


I 


10 


31 


I 





I 





2 


I 














5 


Feb. I 


I 

















2 











3 


2 




















I 


I 








2 


3 


4 





I 





I 


I 





I 








8 


4 




































Total 



44 



27 



32 37 



38 



52 



36 26 



23 



35 350 



26 WILLIAM HOWARD BAT SON 

TABiDE Va 

Subject — F. 

Experiment — Tossing and catching two rubber balls with left hand. Each 
practice was a thousand catches with one minute rest between each 
hundred. The first horizontal row in each group represents the number 
of misses in each hundred. The figures just below show the count at 
which the miss was made. The column at the right shows the misses per 
one thousand catches. 



Trials 


I 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Total 


Jan. 13 


4 


4 


5 


8 


4 


12 


8 


3 


4 


4 


56 


Jan. 14 


5 


5 


4 


8 


9 


6 


2 


2 


I 


3 


45 



28 20 9 II 16 13 74 64 74 39 

44 48 66 13 20 ^ 90 90 46 

49 76 77 34 28 55 84 

58 94 81 41 29 58 

76 97 77 41 69 

88 49 97 

94 51 

100 67 

87 

Jan. 15321557541235 

8 50 87 24 42 II 31 45 32 29 

17 91 60 46 21 42 71 98 

2,2 66 49 40 90 79 

92 6y 43 92 86 

100 85 52 96 

73 



Jan. 


16 


2 


2 


3 


3 


4 


2 


4 


I 


3 


4 


27 






37 


55 


48 


32 


25 


26 


14 


10 


25 


10 








55 


99 


54 
88 


61 
100 


60 

71 

74 


74 


32 
64 
81 




64 
85 


21 
48 
59 




Jan. 


17 


3 


3 


2 


2 


5 


2 


2 


I 


2 


2 


24 



37 


6 


34 


14 


16 


44 


20 


4 


56 


66 


34 


48 


35 


17 


07 


75 




66 


87 


59 






26 











77 
94 



.56 


42 


75 


51 


52 


68 


57 


94 




61 


81 


67 









47 



Jan. 1830302 I 2 105 17 

69 3 

13 
46 
70 
86 



Jan. 


19 


2 


I 


I 








I 


I 





3 


3 


12 






39 

57 


69 


44 






42 


4 




35 
86 
88 


2 

7 
61 




Jan. 


20 


4 





I 





I 





I 


I 


I 





9 






II 

60 
70 




78 




98 




10 


99 


66 






Jan. 


21 


I 





2 


I 


I 


I 


I 


I 





3 


II 



35 10 7 34 17 71 90 67 

79 98 

99 



ACQUISITION OF SKILL 27 

TAlBLE Va (Continued) 

Subject — F. 

Experiment — Tossing and catching two rubber balls with left hand. Each 
practice was a thousand catches with one minute rest between each 
hundred. The first horizontal row in each group represents the number 
of misses in each hundred. The figures just below show the count at 
which the miss was made. The column at the right shows the misses per 
one thousand catches. 



Jan. 


22 


2 








I 





3 


2 





I 


I 


10 






I 
33 






45 




24 
41 
67 


12 
90 




76 


26 




Jan. 


23 


2 


3 


2 





2 


4 


I 


3 





2 


19 






80 
96 


37 
63 

77 


51 
95 




46 
86 


66 
81 
87 
98 


36 


38 

71, 

76 




22 
91 




Jan. 


24 


2 


I 


2 


4 


I 


4 





I 


2 


I 


18 






18 
66 


73 


4 
83 


33 

58 
87 
90 


70 


46 
69 
75 
79 




94 


48 
71 


54 




Jan. 


25 


2 





I 














2 


3 


I 


9 






I 
10 




92 










17 
91 


14 
60 

91 


88 




Jan. 


26 


2 


I 


I 


I 





I 


2 








I 


9 






9 

3.S 


74 


92 


75 




54 


3 
66 






73 




Jan. 


27 


I 


I 


I 


I 





3 


I 


2 


I 


I 


12 






3 


87 


82 


63 




39 
50 
71 


40 


42 
70 


10 


97 




Jan. 


28 





2 





I 


I 


I 


I 











6 








62 

77 




57 


4 


3 


94 










Jan. 


29 











I 

















I 


2 












5 












10 




Jan. 


30 





2 


I 


I 





2 





2 


I 


I 


10 








8S 
87 


54 


95 




47 
74 




32 
70 


89 


52 




Jan. 


31 


I 





I 





2 


I 














5 






79 




56 




60 
80 


50 












Feb. 


I 


I 

















2 











3 






78 












82 
95 










Feb. 


2 




















I 


I 








2 


















75 


I 









Feb. 3 40101 loi 

2 88 75 84 62 

26 

45 
80 

Feb. 400000000 



28 WILLIAM HOWARD BATSON 

Experiment V. Subject H. 
This work was the tossing and catching two balls. No fur- 
ther instructions were given than that the subject should toss and 
catch one ball while the other was in the air. The practice con- 
sisted of five hundred catches, or as near as the score under the 
conditions could be kept to that number, daily. In the last trial 
that commenced below the five hundred, the subject was permit- 
ted to continue until he missed. This sometimes ran slightly- 
over the five hundred. The practice was taken in the evening 
between seven and eight o'clock by electric light. The work 
commenced Feb. 3, 191 4 and continued until March i, 191 4. 
The following days of practice were missed: Feb. 10, 18 and 28. 
The subject had had no previous experience in tossing balls. A 
rest period of five minutes was given as near the two hundred 
and fiftieth catch as it was convenient to make it without stop- 
ping the subject in the midst of a trial. The results of this prac- 
tice are shown in Table VI. 

TABLE VI 
Subject — H. 

Experiment — Tossing and catching two rubber balls with rigtht hand. Each 
practice was five hundred catches with five minutes rest near the 2Soth 
catch. The numbers at which the misses were made are given below. 

Feb. 3—1, 2, 3, 5, 7, 9, 10, 13, 15, 18, 22, 26, 29, 30, 32, 34, 37, 40, 44, 

46 49, 51, 55, 56, 57, 57, 61, 62, 63, 64 67, 70, 73, 75, 78, 79, 80, 

84, 85, 88 ■ 93, 95, 100, 102, 102, 103, 105, III, 112, 116 123, 125, 

129, 133, 135, 139, 140, 148, 149, 153 160, 163, 166, 171, 173, 176, 179, 

182, 184, 186 188, 193, 195, 198, 201, 203, 205, 208, 212, 215 219, 

221, 223, 224, 227, 231, rest period, 232, 233, 238, 240, 241, 251, 265, 276, 

277, 281, 293, 296, 299, 301 — 303, 304, 308, 317, 325, 330, 334, 2Z^, 341, 

343 349, 351, 358, 365, 368, 384, 2,^, 396, 404, 410 414, 418, 428, 431, 

434, 435, 437, 442, 445, 446 449, 454, 455, 460, 465, 468, 474, 477, 

483, 488 491, 492, 494, 497, 500. Total 145. 

Feb. 4—4, 7, 12, 14, 16 19, 21, 23, 25, 28, 31, 34, 38, 43, 46 47, 

49, 49, 58, 64, 64, 65, 71, 75, 77 81, 85, 92, 96, 100, 105, 109, 109, 120, 

120 123, 128, 131, 137, 141, 143, 146, 149, 150, 155 163, 177, 181, 

189, 193, 200, 208, 218, 222, 226 226, 229, 231, 237, 247, rest period, 252, 

253, 258, 263, 268 280, 284, 289, 292, 293, 294, 297, 319, 326, 329 335, 

22>(>, 2,47, 356, 357, 357, 360, 369, 374, 277 381, 383, 394, 400, 409, 412, 

426, 432, 437, 442 445, 446, 448, 452, 458, 461, 463, 469, 475, 481 493, 

496, 496, 498, 502. Total no. 

Feb. 5 — I, 3, 8, 10, 12 13, 18, 22, 22, 25, 28, 28, 28, 34, z'^ 27, 27, 

41, 45, 46, 48, 52, 55, 57 59, 60, 60, 60, 60, 61, 64, 72, 76, 83 83, 

84, 87, 88, 94, 96, loi, 103, 106, 109 no, 119, 126, 131, 135, 140, 141, 141, 

148, 151 151, 152, 152, 158, 161, 164, 168, 174, 175, 188 2QO, 207, 

207, 212, 220 229, 237, 2414, rest period, 245, 245, 251, 252, 254, 255, 256, 259, 

^68, 281, 283, 301 321, 333, 338, 343, 277, 277, 279, 384, 388, 410 ■ 

425, 425, 439, 461, 481, 482, 494, 496, 508. Total 104. 



ACQUISITION OF SKILL 29 

TABLE VI 
{Continued) 
Subject — ^H. 

Experiment — Tossing and catching two rubber balls with right hand. Each 
practice was five hundred catches with five minutes rest near the 250th 
catch. The numbers at which the misses were made are given below. 

Feb. 6— II 14, IS, 21, 24, 32, 38, 44, 45, 47, 67 72, yj, 82, 86, 90, 

91, 92, 97, 99, 103 • 107, III, 130, 143, 151, 168, 174, 182, 190, 205 • 

219, 228, 255, rest period, 261, 280, 285, 311, 326, 333, 336 385, 391, 

428, 430, 431, 433, 461, 475, 485, 501. Total 51. 

Feb. 7— 7, 17, 19. 21, 41, 60, 78, 96, 114, 132 13s, 150, 166, 

167, 175, 179, 181, 190, 195, 201 215, 223, 225, 225, 227, 240, 258, rest 

period, 263, 265, 268 273, 276, 290, 334, 356, 364, 2>77, 381, 400, 

414 423, 444, 453. 455, 479, 486, 504- Total 47. 

Feb. 8 — 2, 3, II 13, 17, 27, 27, 30, 36, 41, 48, 60, 70 90, 94, 

105, 107, no, 121, 133, 141, 143, 150 150, 172, 203, 23s, 267, rest 

period, 279, 226, 290, 300, 310 318, 322, 326, 334, 345, 375, 388, 400, 

403, 407 435, 438, 441, 455, 489, 518. Total 49. 

Feb. 10 — 16, 17, 20, 21 21, 28, 47, no, 152, 160, 173, 196, 201, 202, 

209, 231, 23s, 238, 246, rest period, 253, 260, 264, 267, 268 300, 

330, 343, 346, 376, 401, 416, 432, 449, 452 510. Total 35. 

Feb. II — I, 98, 129, 130, 153, 165, 193, 213, 272 rest period, 280, 

287, 324, 339, 381, 421, 430, 442, 504- Total 18. 

Feb. 12 — 39 — 60, 81, 100, 122, 176, 194, 221, 281, rest period, 290, 

318 450, 489, 499, 560. Total 16. 

Feb. 13 — 49, 93, III, 116, 121 143, 182, 249, rest period, 274, 315, 

2^, 410, 431, 509. Total 15. 

Feb. 14 — 0, 42, 69, 131, 190, 203, 238, rest period, 214, 264, 284 301, 

3Z^, 364, 2>^7, 372,, 389, 409, 418, 4SO, 453 460, 471, 535- Total 22,. 

Feb. 15—6, 21, 31, 59, 78, 88, 89 116, 135, 150, 169, 174, 185, 193, 199, 

204, 205 244, 246, 247, 255, rest period, 257, 272, 285, 288, 289, 

323 227, 344, Z^^, 369, 379, 383, 409, 427, 428, 438 472, 488, 494, 

505. Total 41. 

Feb. 16 — ^56, 84, 124, 152, 158, 200 219, 223, 234, 242, 296, rest 

period, 299, 311, 350, 359, 386 — 391, 395, 402, 446, 497, 5o6. Total 22. 

Feb. 17 — 15, 21, 44, 83, 130, 138, 163, 216, 261, rest period, 287, 309, 407, 
428, 432 492, 524. Total 16. 

Feb. 19 — 99, 130, 178, 208, 235, 252, rest period, 290, 328 352, 416, 

428, 454, 5 18. Total 13. 

Feb. 20 — 97, 159, 200, 240, 268, rest period, 322, 352, 413, 459, 537. 

Total II. 

Feb. 21 — 31, 47, 61, 99 ■ 126, 131, 149, 150, 162, 180, 185, 216, 217, 

233 243, rest period, 263, 267, 278, 2>27, 3^2, 373, 4i3, 4i5, 

434, 455, 460, 46,1, 523. Total 29. 

Feb. 22 — 24, 54, 91, 91, 109 134, 145, 171, 220, 247, rest period, 261, 

335, 377, 428, 436 456, 463, 474, 476, 477, 489, 494, Si7- Total 23. 

Feb. 23 — 15, 116 149, 186, 208, 237, 298, rest period, 340, 369, 434, 

500. Total II. 

Feb. 24 — 32 61, 200, 205, 231, 322, rest period, 335, 449, 537. Total 9. 

Feb. 25 — 86, 114 189, 234, rest period, 516. Total 5. 

Feb. 2& — 53, 87, 187, 266, rest period, 348, 415, 435 551. Total 8. 

Feb. 27 — ^227, rest period, 435, 509. Total 3. 

March i — Z2>2, rest period, 550. Total 2. 

The table shows the number at which the misses were made, 
that is in the first practice the subject caught one ball and missed 
the second one. The next trial he caught one more and then 
missed. This makes two catches as represented by the two. By 



30 WILLIAM HOWARD BATSON 

taking the difference between any two successive numbers, the 
number of catches made during that trial may be found. The 

breaks, marked " " in the columns divide the work into 

periods of ten trials each. This was done for convenience in 
plotting one of the curves. The last figures marked "total" show 
how many misses were made in that particular practice period. 

The Plotting of the Curves 

In order that the significance of these figures may be better 
understood, the curves which they represent have been plotted. 
Curves I, II, III, IV and V (Plate I) are plotted by letting the 
divisions on the x-axis represent the practice periods and the 
divisions on the y-axis, the number of catches. In Curves VI 
and VII (Plate II), the divisions on the x-axis represent the 
number of practice periods and the divisions on the y-axis rep- 
resent the number of misses in the practice period. Curve VIII 
(Plate III), also, has practice period divisions on the x-axis and 
the number of catches on the y-axis. Curve VIII is obtained by 
taking the work of Subject H. and finding how many catches 
were made in each ten trials. Since he was not stopped at the 
end of any trial, the only difference between this and the first five 
curves is that the practice was differently distributed. Each 
practice period for Subject H. continued until he had caught five 
hundred or a few more than five hundred balls. In Curve VIII, 
each ten trials is called a practice period and given a space on 
the X-axis. 

Curves IX and X (Plate III) are obtained by taking the sec- 
ond part of the work of Subject F. and the work of Subject H. 
and using the riciprocals of the number of trials for the divisions 
on the y-axis and the number of practice periods for the divi- 
sions on the X-axis. The number of trials and the number of 
misses are the same for Subject H. But for Subject F. one 
trial must be added in each hundred as the last one was not 
counted a miss. This places him at a disadvantage as he was not 
allowed to finish out his last trial. Under the given conditions 
these reciprocal curves have the same form as the curves that 
would be obtained by taking the average number of throws per 



ACQUISITION OF SKILL 31 

trial in the given practice period, which in these cases includes 
one thousand or five hundred catches for the divisions on the 
y-axis. 

Curves XI, XII, XIII, XIV (Plate II) and XV (Plate III) 
are plotted by taking groups of one thousand tosses for the di- 
visions on the X-axis and the average nuuber of catches per trial 
for the divisions on the y-axis. Tables I, Ila, lib, III and IV are 
used as a basis for the data. Each table is divided into as many 
groups as there are thousands of catches. Where a thousand 
catches ended in the midst of a trial the number that was used 
out of that trial was used as a fractional part of a trial. For 
instance, if the first one thousand included the sum of the number 
of catches made in the first fifty trials and a half of the number 
of catches made in the fifty-first trial, then the whole number of 
trials for the first one thousand would be fifty and one half. 
This divided into the one thousand would give the average num- 
ber of catches per trial in the first one thousand. In each of these 
tables there was a fractional part of a thousand left over. The 
curves do not show this. 

Another way of handling the data was to divide the catches 
in each table into groups of one thousand each and then to find 
what per cent each thousand catches was of the total number of 
tosses for making a thousand catches. For instance, in Table I, 
it is found that in order to make the first thousand catches 11 72 
+ tosses (1000 catches plus 172 trials) were necessaary. This 
gives 85 per cent of success. In each succeeding thousand as 
the number of trials per thousand catches becomes less the 
percent of success becomes greater. Curves were plotted on this 
basis and Curves Ila and IVa (Plate I) are typical examples. 

Curves were also plotted by taking the highest score in each 
one thousand group for divisions on the y-axis and the thousand 
groups representing divisions on the x-axis. Curves Illb and 
IVb (Plate I) are typical examples obtained in this way. 

Discussion of the Curves 
Curve I, II, IV, and V have a rather long period during 
which they rise but little. It took twenty practices for Curve I to 
rise above the one hundred level. Half of the number of prac- 



32 WILLIAM HOWARD BAT SON 

tices were spent before the two hundred mark was reached. The 
drop in the curve at the twenty-fourth and the fortieth practices 
was the result of the room being cold. The drop at the thirtieth 
and thirty-third practices was caused by those apparently un- 
accountable bad days for which there was no reason that could 
be pointed out. • 

Curve II shows that the practice commenced further along. 
It is, however, slightly concave to the y-axis. Curve III has a 
more typical form for this method of plotting the work. There 
is a period of slow rise extending over more than half of the 
practice periods. The two hundred mark was not reached until 
the twenty-fifth practice. The thirty-sixth, thirty-seventh and 
thirty-eighth practices were on the three days just before the 
Christmas vacation and this seems partly, at least, to account 
for the drop here. It will be seen that after a period of eighteen 
days rest, the score on the thirty-ninth practice is nearly as high 
as it had ever been before. 

Curve IV shows a very slow rise but without any very marked 
fluctuations. It took thirty-six practices for the subject to 
reach the two hundred mark, and he did not rise above it per- 
manently until the fiftieth practice. The fluctuations between 
the forty-fifth and fifty-second practices represent the period just 
before and after the Christmas vacation. In this case there was 
a slight fall in the score immediately after the practices were 
resumed. 

Curve V is peculiar in that it shows a very marked decline 
period. This is, no doubt, the result of too much effort. The 
subject was very anxious to reach the mark set which was to 
make an average of a hundred per trial for two consecutive 
days. After he made the score on the forty-ninth practice, he 
tried very hard to make a thousand catches in the ten trials on 
the next day. He said that his attention was so set on making a 
thousand catches that he forgot how to throw. His failure 
caused a temporary period of despondency. He thought he 
never could reach the mark set. 

The higher level from the nineteenth to the thirty-fourth prac- 
tice may be explained by the fact that the practices were daily; 



ACQUISITION OF SKILL 33 

before this time they had been on alternate days. The curve 
shows a somewhat higher level at first than do the other curves. 
This is possibly due to the subject's previous practice. 

Curves VI and VII show a very rapid drop at first and then 
a slower fall toward the end. The fluctuation in Curve VI, 
perhaps, would not have appeared had the subject not had to 
practice in a cold room and had he been in a good physical con- 
dition. Curve VII has two marked rises. The first marked rise 
at the eleventh practice is the result of subject's being in a bad 
physical and mental state. At this practice he stated that he 
had had a disagreeable conversation just before and that he 
was all "worked up." He had been up late for several nights. 
He stated that his head and eyes ached and that he had no con- 
trol of his hand. The next night he said that he was all worn 
out, that he had a cold and that he did not think he would ever 
be able to get below the mark that he had already set. 

The rise at the seventeenth practice was due to the subject 
being in a hurry to get to orchestra practice. In these cases 
where the practice period is long, it appears that the fluctuations 
under normal conditions would be rather small. Subject H. felt 
confident after he had finished that if he had not tried to take 
the practice under adverse conditions, he would have had a 
nearly smooth curve. 

When the work of Subject H. is reduced to a ten trial basis, 
the form of the curve does not differ greatly from the first five 
curves. It does not appear that the heaped up practice has any 
effect on the general form of the curve. In the curve only six 
trials are represented on the last division of the x-axis and yet 
the score for these six trials is more than twice as large as that 
for any other ten trials. 

When the reciprocal of the number of trials is used as a 
measure of the skill, the curves take the form of IX and X. As 
has been stated. Curve IX is defective because the last trial in 
each hundred is not complete. The subject was stopped when he 
reached a hundred. 

Curve X has a form similar to the first five curves, — that is 
it is concave to the y-axis. It has a slow rise at first and a rapid 
rise at the end. 



34 WILLIAM HOWARD BAT SON 

Curves XI, XIII, XIV, and XV are all to a certain extent 
concave to the y-axis. By taking groups of a thousand instead 
of ten trials as a basis for the divisions on the x-axis, the early 
part of the curves rise more rapidly but even in these cases the 
latter part of the curves shows a rapid rise. 

Curve XII corresponds to Curve II plotted by letting the ten 
trials represent the divisions on the x-axis. In this case where 
the groups of one thousand represent the divisions on the x-axis 
there is a slight convexity to the y-axis. It approaches more 
nearly a straight line. 

Curves Ila and IVa rise rapidly at first and then approach 
parallelism with the x-axis. Curves obtained by taking the 
highest score in each one thousand group as a basis for divisions 
on the y-axis, of which Curves Illb and IVb are examples, ap- 
proach a straight line in general form. In none of these curves 
is there evidence of an arrest period of any considerable length 
between two periods of rapid rise. 

Discussion of Results 

It was the intention in this part of the work, to change the 
conditions so as to give a chance to analyse the factors involved 
and thus to get a better idea of how they influence the acquisition 
of skill. 

Experiment' — I : The purpose here was to get a curve for 
comparison where no directions were given and the subject was 
free to learn as he pleased. The first difficulty he noticed was 
his inability to throw the balls properly. This was such a bother 
that it was necessary to move to a larger room on the third day. 
This did not seem to aid any as he made a lower score on that 
day than on the day previous. The subject had great confidence 
throughout the work and was always sure that he was going to 
do better than on the preceding day. He noticed after the third 
trial that he fixed his attention on the ball at its highest point. 
On the twentieth day, when he reached a score more than twice 
as large as he had ever made before, he could give no other 
reason for the improvement than that they just seemed to fall 



ACQUISITION OF SKILL 35 

right. A cold room had a very marked effect upon the score 
as is shown by the resuh on the twenty-fourth and fortieth 
practice days. 

Experiment — II : After two trials the subject had control of 
the manner of throwing to a large extent. In the fourth trial, 
all the attention apparently was centered on the throwing and 
the trouble came in the balls rolling out of the hand. In the 
fifth trial there was a greater feeling of confidence. The sub- 
ject knew that he had reached a higher level of ability. At the 
ninth trial there was trouble because of the balls hitting together 
in the air. This difficulty lasted until the end of the practice. 
If the thought of their hitting together came up, they were almost 
sure to do so. 

When the left hand was used, it was just the same as be- 
ginning all over again. The ability to grasp the ball came 
slower. It was noted at the eighteenth trial that this power 
had increased. It was also noted at that time that there was 
increase in ability to place the hand so as to receive the ball. 

Experiment — III : The subject's first object was to pitch in 
a curve from right to left. His eyes seemed to follow the ball 
in its course and then with a quick jerk he threw the second ball 
and attempted to catch the first. The tendency was for him to 
follow the ball around in a circle from right to left. He was 
encouraged to follow the plan of pitching rather than to aim 
to make a high score. In the third trial, he thought there was no 
hope; his trouble was all in catching. He was still urged to 
give all his attention to throwing and get that under control first. 
In time, he did succeed in mastering the plan of throwing but 
an improvement in all the other elements of the work went along 
with this improvement. The subject was very sensitive to a 
cold room and the low score on Dec. 14 was the result of this. 
The missing of a few practices did not seem to effect the score 
either way to any great extent. After the Holidays, when the 
practice had been discontinued for seventeen days, his score fell 
slightly below what it had been the last two days before the 
vacation but these had been unusually high. 

Experiment — IV: The purpose in using hard rubber was to 



36 WILLIAM HOWARD BATS ON 

compel the subject to throw in a certain way. At first there 
was a tendency to throw the pieces so far away that he could 
not reach them. At the ninth trial on the first day, he com- 
menced to throw in a circle from right to left. On the sixth 
day, he changed his plan of throwing because the pieces had 
whirled end over end. He now tried to pitch them straight up 
and let them fall fiat on his hand. On Nov. 30, the low score 
was made because the subject was trying out a new plan of 
throwing. He now let the pieces, roll off the ends of his fingers. 
He continued to use this method but in most cases when the 
pieces did whirl end over end he was able to get them started 
properly and would thus recover. 

In the practice of all the subjects, a large part o£ the improve- 
ment seemed to be in their ability to get out of tight places. 
Ordinarily the throwing would go smoothly for some time until 
a bad pitch or catch would put one in a difficult position to make 
the next move. Early in the practice, this would mean a miss, 
but later the subject would be able to recover and get them going 
correctly. Subject F. thought his ability to get out of bad places 
was due to his giving attention to the next throw rather than 
centering all attention on the catch about to be made. 

In the second part of this experiment, the object was to see the 
effect of giving a longer practice period. These results are shown 
in Curves VI and IX. 

Experiment — V : This experiment had the same object as the 
second part of the experiment above. The subject was not at 
all given to any form of athletic work and took but little interest 
in physical exercise. He tried to study every phase of the work. 
At first he had very little confidence in his ability to do the catch- 
ing. In the second practice, he noticed that he recovered a num- 
ber of times from bad places. In the fourth practice, he found 
that the chief trouble was fatigue. He now felt confident that 
he could make a good score. 

Taken as a whole, the subjects were affected more by sub- 
jective and objective factors in the beginning of the work than 
after they had reached a high degree of efficiency. The sub- 
ject's feeling that he was going to make a high score was no 



ACQUISITION OF SKILL Z7 

guarantee that he would do so. At times both high and low 
scores were made without the subject being able to account for 
them. An extra effort had no noticeable effect in increasing 
the score. In the early practice, there was a great amount of 
useless effort. The other hand would work in harmony with 
the one that was being used, the feet would be shifted with every 
catch, and the whole body seemed to be affected. When the 
skill, became greater, the unnecessary movements dropped out. 
They would return, however, when the subject found himself 
in a tight place but as soon as he got control they ceased. 

By a study of the curves, it is seen that an attempt to give 
attention to different phases of the work does not modify the 
general form of the curves for this work. There seems to be 
scarcely any room for doubt that although some one factor may 
be picked out and emphasized, all the elements improve together. 
In this work having a method did not help much and nearly all 
the improvements were made accidentally and then adopted. 
The Warming up Process 

A good idea of this may be obtained by taking the sums of the 
trials separately for the different subjects. The following are 
the figures : 

1st 2nd 3rd 4th 

Subject — D. 11134 943 1357 1261 

" B. 927 1359 1244 1 189 

" B. 1210 149s 1470 1416 

" W. 1458 1978 2051 2097 

'* F. 1409 2800 2232 2410 

Total 6138 857s 8354 8373 8956 7379 7881 8129 7066 8573 

From the figures in the total, it is seen that the first trial falls 

almost a thousand below any other trial. In three cases it is 

below any other of the ten. In the other two cases it is below the 

average for the ten. 

Relearning 
None of the subjects shows any considerable loss for a long 
rest period. Subject D., on Aug. 15, after a rest of 265 days, 
was able to make a score higher than any he had ever made before 
excepting the first three at the end of the practice where he had 
made a sudden rise. Two days afterwards without any further 



sth 


6th 


7th 


8th 


9th 


loth 


II69 


958 


1157 


1616 


ins 


1396 


1372 


1416 


1340 


1245 


107s 


1752 


I6II 


1241 


1233 


1332 


1 142 


1466 


2338 


2079 


1793 


2184 


1883 


2008 


2466 


188s 


2340 


1752 


1852 


195 1 



38 WILLIAM HOWARD BATSON 

practice he was able to make a score that almost equalled his last 
practice score. After nearly a year (327 days) more had elapsed, 
he was able to make the very high score of 2550 which was al- 
most twice as high as he had ever made before. Here the only 
thing that seemed to bother him was the fatigue. 

Subject-B. after more than a year's rest (613 days) made 
nearly as good score with the right hand as he had ever made 
before. He was sure he could have exceeded any previous score 
if he had not fatigued himself so much by the first throw (score 
329). After that he could not grasp the balls so well. After the 
beginning of each trial was made the work went along without 
much trouble. The next day, he surpassed any previous record 
with a score of 1437. Here the fatigue element, especially that 
of the eyes, was very annoying. 

The left hand, after a period of 612 days, seemed to have lost 
more. The process seemed very strange and the subject had no 
confidence that he could do it. Even in this case the score did 
not fall much below what it had been before the last two times 
in the regular practice. Two days later the subject was able to 
make a score of 702. This exceeded any score he had previously 
made except the last three of the regular practice. 

Subject-W., after a rest of 134 days, was able to reach a score 
higher than any he had before made except the last four in the 
regular practice. The next day he exceeded all previous records. 
After a period of 371 days from this practice he was able to 
make a score higher than any he had ever made before. The 
only explanation he gave for this is that he had been out playing 
tennis and felt especially well that morning. 

Subject F'., after a period of 143 days seemed to have dropped 
to a level that preceded his last two practices. The next day he 
was not able to do so well. The first day he started out confident 
that he would exceed an average of a hundred catches per trial 
but after a bad run in the seventh trial he became discouraged 
as the figures show. 

Taken as a whole the results show that there remains for long 
periods of time after practice ceases an ability about equal to 
what it was at the end of the practice. In some cases it seems 



ACQUISITION OF SKILL 39 

to increase and in nearly all cases is capable of a very rapid in- 
crease when practice is commenced again. 

The Total Amount of Practice 
In the first five experiments, attention has been called to the 
amount of practice that passed before any great amount of ad- 
vance was made. This must not be taken to mean that a propor- 
tionate part of the practice time had passed. In the trial method, 
the first ten trials gave but very little practice. The amount of 
actual practice increased as the ability increased. This, of course, 
is not the case where a certain number of catches had to be made 
each day or practice period. 

The total number of catches gives an idea of -the total amount 
of practice and may be a truer index of the subject's ability to 
improve. It is seen from these figures that Subject D. took the 
least practice (12124 catches) although he took more practice 
periods than did Subject B. The figures show further that Sub- 
ject B. improved almost as fast with the left hand as with the 
right hand, the catches being 136 17 and 129 19 respectively. 
However, the practice with the left hand is distributed over a 
longer period. This might mean that the left hand improves 
about as fast as the right hand or that the longer distribution 
has the advantage. 

Subject W. took 20180 catches to gain the degree of skill re- 
quired of the other subjects. Subject F. took 21098 catches but 
his work was much more difficult. 

THE EFFECT OF AN ISOLATED FACTOR 
While doing the work just discussed, it was noticed that several 
factors influenced the subject's progress. At least three of these 
could be easily picked out. It has already been noticed that the 
ability to throw the ball so that it could be reached was an im- 
portant element in the learning. This judgment of direction or 
the ability to throw properly is one of these elements. 

Again, the force with which the balls were thrown was im- 
portant. If the ball was not thrown high enough, it would 
return before the other could be thrown. Not all the subjects 



40 WILLIAM HOWARD BATS ON 

used the same force, or in other words pitched the balls the same 
height, but they soon fell into some habit of pitching and when 
the work was going smoothly, about an equal amount of force 
was put into each pitch. The element of force was the second 
factor to be noticed. 

The third element is that of time. It has been stated that the 
eye saw the ball only at the highest point of its upward motion 
and a short way down on its course. The absolute eye movement 
was not measured but by watching the subject's eyes it was seen 
that they scarcely moved in a vertical line. It was necessary for 
the subject to learn to catch the ball by timing it from the time 
it left the field of vision until it reached the hand. That thin 
was the case is shown by the subject's inability to grasp the ball 
at first when it hit his hand or by his closing the hand too soon 
and permitting the ball to hit the ends of his fingers. That this 
grasping is not simply a reflex that takes place after the ball 
hits the hand is further shown by taking a practiced subject and 
intercepting the ball after it leaves the field of vision but before 
it reaches his hand. It was found that the hand closes even 
though the ball does not touch it. 
~Y These three elements, judgment of direction, judgment of 
;| force, and judgment of time, have been selected for further study. 
-^The aim was to discover the nature of the improvement of these 
factors when isolated and trained in as simple a form as it was 
possible to devise. 

Experiment I. On Direction 
Two subjects took part in this experiment: Subject D. (De- 
Camp) and Subject W. (Wang) had both been subjects in the 
ball tossing experiments. The apparatus consisted of a smooth 
board, a steel ball, and a small block of wood. The board was 
fifteen inches wide and about fifteen feet long. Forty and one 
half inches from one end of the board a line was drawn across 
at right angles to the side. On this line, inch spaces were marked 
off and numbered from zero out on one side to plus seven and 
on the other side to minus seven. Seven and one half feet from 
this line another line was drawn across the board. The board 



ACQUISITION OF SKILL 41 

Avas three and one half inches higher at the first mark than at 
the second mark. 

The steel ball was one inch in diameter and weighed 66.8 g. 
The block of wood was two and one half inches long and seven 
eights of an inch square. This was set up on the zero mark as 
a target. The subject stood at the lower mark and rolled the 
ball at the block of wood. His score was kept in figures as 
-|-i, — 3, etc. accordingly as the steel ball passed through these 
numbers or spaces.* 

Subject W. commenced this work on Apr. 14, 191 3 and con- 
tinued it until May 18, 191 3. The practice was daily in the 
forenoon and consisted of fifty trials. The result of this worl>c 
is shown in Table VII. 

TABLE V'll 
Subject — W. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 

April 13. o, 2, I, o, 2, — ^7, 2, 0, — I, I, o, — 7, 6, 2, I, 2, I, 3, o, — 5, I, 
— 2, 3, o, — 2, 3, 5, o, o, o, o, 2, 2, — 4, o, 2, — 5, o, o, — 2, 4, o, 
o, 3, 3, 3, o, o, o, —I = 90. 

Apr. 14. o, — 4, — 4, — 2, — 3, 2, — I, — I, o, — 2, o, — 2, — 2, — I, — I, o, o, 
2, — 2, o, I, — 2, o, — I, o, o, 2, 2, I, — 2, — 3, — 2, — I, — 2, o, o, — 2, 
o, o, 2, 3, — 2, — I, o, o, — 2, I, — I, o, I = 63. 

Apr. 15. 2, 2, I, o, — ^i, o, o, o, o, o, o, o, i, o, i, — i, i, — ^5, 4, 
2, o, — 3, — 2, I, 2, 2, I, — I, o, o, — I, o, o, — 3, 7, o, — 3, — 4, — 4, 
o, o, —I, —I, —3, o, —3, —4, —3, —2, —I = 73. 

Apr. 16. I, o, I, 2, 2, o, 2, 2, o, o, o, — I, o, o, — i, i, o, — 3, o, o, 
o, — 4, o, — I, o, o, o, — I, — 2, o, — I, o, o, o, — 2, — 2, 2, — 4, I, o, I, 

O, 2, O, O, I, — I, — 2, I, I r= 44. 

Apr. 17. I, 2, o, — I, — I, 2, I, 2, I, I, o, o, I, 2, 2, o, I, o, o, o, o, 
o, 4, 2, o, I, o, — 3, 2, I, I, — 3, o, — I, o, o, o, o, o, o, — I, 0, I, 

O, I, O, I, 2, — 2, — 5 := 49. 

Apr. 18. — 2, 2, I, o, I, — 2, o, 3, o, I, — 4, o, I, o, I, I, o, o, o, o, 2, 

O, — I, — 2, O, O, O, O, — I, — 3, I, 2, I, O, O, — 2, I, — 3, — I, — I, O, — 4, 2, o, 

o, o, — I, 0,0,0=: 47. 

Apr. 19. I, I, 2, — 5, — 3, o, — 2, — 2, o, — 3, o, 5, 2, 2, o, — 4, 2, o, 

0, — 'S, o, — 3, I, I, o, 2, o, I, o, o, Q, — 3, — ^i, o, — I, o, o, o, i, 
— I, 2, o, o, 4, o, 3, o, I, o, I = 65. 

Apr. 20. 2, 2, 2, o, I, o, — 2, — 4, I, o, 2, o, — I, — 2, 2, o, o, 2, o, o, o, 
— 2, — 2, 2, 2, 2, 2, O, O, — I, I, O, I, o, o, O, — 2, — 3, O, — 2, o, O, — I, 
2, I, 2, 0, O, 0, O, = 51. 

Apr. 21. o, o, — I, o, I, o, I, o, o, o, i, — i, o, o, o, — 3, 2, 2, i, o, 3, 2, 

— 2, 2, O, 2, I, O, O, 2, O, — 2, 0, — I, I, 0, O, — '3, 2, O, I, 2, — I, — I, 

2, 0, — I, 3, — I, o = 48. 

Apr. 22. 2, — 2, O, I, O, — I, o, o, O, 2, o, o, o, O, — 2, — I, — 3, I, o, o, o, 

1, O, 2, I, o, o, o, O, — 3, I, I, — 2, O, O, — I, — 3, — 4, 0, — I, O, I, I, 

I, — I, O, — 2, —I, O, 4 =1 46. 

* In order for these figures to correspond to the valine they represent, the 
divisions should have been weighed according to the divisions on the base 
line of the curve of probability. But as there w^ere relatively few high 
scores the error in the final result was negligible. 



42 WILLIAM HOWARD BATSON 

TABLE VII 
{Continued) 
Subject — W. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 

■Apr. 23. o, — I, — I, o, — 2, o, 2, I, — 4, 2, 2, — 2, o, I, o, o, o, — i, o, o, 

2, I, 2, 2, — I, 2, o, — 4, o, 2, I, I, o, o, — I, — 2, 2, I, I, o, I, o, 
—2, o, o, I, —I, —3, I, —3 = 56. 

Apr. 24. — I, o, —2, — I, o, — 3, I, o, — I, I, — I, — 2, o, o, o, o, i, o, o, 

1, 0, 2, I, o, o, 2, o, o, o, o, o, o, 2, — 5, o, I, 2, o, o, I, 2, 2, 2, 
o, I, o, o, I, 2, I = 43. 

Apr. 25. o, I, 2, o, I, o, o, I, o, I, o, — I, o, 4, i, o, i, i, — 4, i, o, — i, o, 

— 2, o, o, — 7, 3, I, o, — 2, — 2, o, — 2, o, — 6, o, o, I, I, o, o, o, o, — I, o, o, 
—3, o, = 51. 

Apr. 26. 3, — I, — 6, 2, — 3, — 2, 0, — I, I, o, — 2, I, — 2, o, I, o, I, 

o, I, o, o, 3, —4, o, o, —3, —3, I, 0, o, —2, —4, I, o, —3, —I, o, 

2, I, o, o, I, o, o, o, — 4, I, o, 2, o, 2 = 65. 

Apr. 27. I, o, I, I, 2, 2, o, o, 0, 2, I, I, 2, 2, 3, I, o, — I, — 4, 0, 

— 4, I, 2, o, o, o, I, 4, o, — 2, — ^4, o, o, — 3, I, I, o, I, I, I, 
o, o, I, o, o, I, — 3, I, — I, o = 57. 

Apr. 28. o, — 3, o, o, o, I, o, — 4, — I, o, o, — 2, o, o, i, o, — 2, o, o, o, 

o, — I, o, 5, o, — 3, o, — 4, o, I, — 2, I, o, — I, I, o, — 4, — 2, I, o, 
o, I, o, — I, o, — I, I, 0,0,0 = 44. 

Apr. 29. I, I, 2, o, o, o, I, o, o, I, o, o, o, — 3, 0, o, o, o, o, — 2, 

O, 2, O, — 2, — 2, O, O, O, O, I, O, I, O, O, O, I, O, — I, — 2, 2, 

o, o, I, o, — 2, o, — I, o, — 2), o = 32. 4. 

Apr. 30. o, I, o, o, o, — 2, — 2, — 3, o, i, o, 2, — 2, i, o, o, o, — i, i, — 4, 

O, — 2, — 2, O, I, O, O, 2, O, — 2, — 4, I, — I, — I, O, O, — I, O, I, — 2, 

0, O, O, — 2, I, — 2, 0, — I, O, O =46. 

May I. — I, o, o, i, o, i, — 3, i, 4, o, i, o, — 2, — 2, o, — 2, i, o, 2, o, 

1, — I, — 4, 0, — I, — 3, o, o, — 5, o, o, o, o, o, o, — i, — i, — 3, i, — 2, 
o, o, — I, — 4, — I, — 2, — 3, o, I, o = 56. 

May 2. I, — 4, o, 0', i, — 4, 0, — 3, — 4, i, — i, o, — i, o, o, — i, o, o, — 4, 
O, O, O, O, 0, — 5, — 2, — I, o, o, 0, O, I, I, — 3, O, O, — I, o, o, 
O, O, O, — I, O, O, O, O, I, O, — I =: 42. 

May 3. 3, o, I, o, o, i, — 2, i, o, i, o, o, o, i, i, o, o, i, — i, o, 
o, o, I, o, o, — ,1 o, o, o, I, — 3, I, o, I, 2, o, I, o, — I, I, 

O, O, — I, O, O, — 2, O, O, — I, O = 30. 

May 4. o, o, o, o, o, o, o, o, — i, o, o, — i, o, o, o, o, o, o, o, o, 

— 3, — I, — 3, o, o, 0, — I, o, o, O, O, O, O, O, O, O, O, I, o, o, 
o, o, — I, o, o, o, o, o, — I, o = 13. 

May 5. o, — i, o, — i, o, i, o, o, — i, o, o, o, o, o, o, o, i, o, o, o, — 3, o, 

— 4, o, 0, — 2, o, o, o, o, o, o, o, o, o, o, o, o, o, o, o, — 3, o, o, 
o, I, o, 0,0,0= 18. 

May 6. i, o, o, 0, o, o, i, i, — 3, — 2, o, — 2, — 4, o, o, — i, o, — i, — i, i, 

— 3, — I, — I, O, — I, o, o, o, o, o, o, o, o, o, o, o, o, o, o, o, o, o, 

0, o, o, o, o, — 4, 0,0 = 28. 

May 7. 2, o, o, o, o, o, o, o, o, o, o, i, o, o, o, — 2, i, i, o, i, o, o, 

1, o, o, o, o, o, — 3, o, o, o, o, o, o, o, o, o, o, O, O, — I, Oj o, 
0, o, o, — I, 0,0= 14. 

May 8. o, o, o, o, o, — 2, o, o, o, o, o, i, 6, — 3, o, — i, o, o, — i, o, o, 
O, — I, O, I, 2, o, o, o, o, o, o, o, O, — I, o, O, O, O, 3, o, o, 
O, O, O, 0, O, 0,0,0 = 22. 

May 9. — I, — I, — 3, — I, — I, — 2, — I, o, o, o, o, 2, o, o, o, 3, o, o, o, 3, o, 

O, O, 2, O, O, 2, O, O, O, O, O, I, — 2, — I, — I, 3, O, 0, — I, O, — I, — I, 
O, O, — I, O, O, — 2, O = 36. 

May 10. o, o, o, o, o, o, o, o, i, i, o, o, i, o, o, o, o, o, i, o, o, o, 

O, I, I, 2, I, I, O, I, o, o, o, o, o, o, O, O, O, O, — 3, — 2, 

o, o, o, o, o, 0,0,0= 16. 



ACQUISITION OF SKILL 43 

TABLE VII 
{Continued) 
Subject — W. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 

May II. o, o, o, o, o, i, — i, o, o, i, 2, o, — 3, — i, o, o, o, o, o, o, o, 0, 
— 2, o, o, o, o, o, o, o, — I, o, o, — I, o, o, o, o, o, o, o, o, o, o, 
o, o, o, 0,0,0= 13. 

May 12. o, o, o, o, o, o, — i, o, o, o, 0, o, o, o, o, o, o, o, o, o, o, 
o, o, o, O, O, O, I, o, O, O, 0, o, o, O, — I, — I, o, O, O, 0, o, o, 
o, o, o, O, O, I, o = 5. 

May 13. — I, o, o, o, I, o, o, o, o, o, o, o, i, o, o, o, o, o, o, i, o, o, 
o, o, o, O, O, I, O, O, O, O, I, O, — I, I, o, o, o, o, O, 0, o, o, 
o, O, O, I, 0, o r= 9. 

May 14. o, o, i, o, o, — i, i, o, o, o, o, o, o, i, o, o, o, o, o, o, 0, o, 
o, o, o, o, o, o, o, o, o, o, o, o, o, o, — 3, o, o, o, o, O, O, O, 
o, o, I, o, — I, = 9. 

May 15. I, I, o, — 3, —3, o, — 2, O', o, o, o, o, o, o, o, o, o, o, o, o, o, — i, 
o, 0, O, — I, O, O, O, 0, o, o, O, O, O, 0, o, O, O, 0, O, O, 0, 0, o, 
O, O, 0,0,0= 12. 

May 16. o, o, o, o, Q, o, 0, o, o, o, o, o, o, o, o, o, o, o, o, 

o, o, o, o, o, o, o, O, O, I, 0, o, o, o, o, o, o, o, o, o, o, o, 
o, o, 0, o, 0, 0,0, O =^ I. 

May 17. — I, 3, I, o, o, o, o, o, o, o, — i, o, — i,, o, i, o, o, o, 0, o, o, o, 

o, o, o, o, o, o, o, o, o, O, 0, o, o, o, o, o, o, o, o, o, 
o, O, O, O, — I, o, o = 9. 

May 18. — I, o, — ^i, o, — I, o, o, o, o, o, o, o, — i, — i, o, — i, o, — 2, o, o, 
O, O, O, I, o, O, 0, o, o, o, o, o, O, O, — 2, o, o, o, o, o, o, 
O, O, O, O, O, O, O, O, O = II. 

May 19. o, o, o, o, o, o, o, o, o, o, o, i, o, o, 0, i, i, o, 
O, I, o, O, I, o, o, o, O, I, O, O, O, I, O, O, I, O, O, I, o, 
O, O, 0, 0, 0, 0, O, 0, I, I, — I = 12. 

Subject D. commenced work on Apr. 17, 191 3 and continued 
until May 22, 1913. His practice was in the forenoon and con- 
sisted of a hundred trials. The results of his work are shown 
in Table VIII. 

TABLE VIII 
Subject — D. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 
Apr. 17. — 2, — 2, — 3, — I, — I, — 2, o, o, o, I, o, o, o, — I, o, i, 2, o, o, 

0, o, o, — I, — 2, o, o, o, o, o, o, o, — I, — I, o, o, — 3, I, 2, o, o, o, 

1, O, O, O, — I, 2, 2, O, O, I, O, O, 2, O, O, I, O, O, 3, — 2, — 2, 
— I, I, — A, 3, I, 3, — I, — 3, I, o> 2, 2, — 2, O, O, O, 2, 6, — I, 
— 2, o, — 2, o, — 2, 5, o, 3, 4, — 3, o, I, o, 2, o, o, — I = 104. 

Apr. 18. — 4, 2, o, 2, 3, 2, o, — 3, — i, 5, — i, o, o, —5, o, — 4, 

3, O, — I, — 5, O, — I, — 2, — 2, O, O, — I, 4, O, O, 0, 2, o, — 3, 
O, — 2, 2, — I, I, 2, — 2, O, — 3, — I, 2, O, 3, 3, O, I, O, — I, — I, 

o, o, I, — I, o, — I, I, o, 3, — I, — 3, o, — I, o, o, — I, — 3, — I, 

— I, I, O, 2, O, O, — I, 3, O, 2, O, 2, 0, O, 2, — I, 0, — I, O, 
' — 2, — I, — I, I, — I, 2, — I, O, 2, O = 125. 

Apr. 19. — 3, o, 4, o, I, o, o, 2, — 7, o, o, i, 2, — i, i, 2, 

0, I, — 3, 3, o, 5, o, I, I, o, I, I, o, I, — 3, o, 0, o, o, o, 

1, O, 3, I, I, — I, I, I, 3, I, I, I, 4, o, 2, o, O, O, O, 2, 

2, 3, o, 3, o, o, o, 2, I, o, I, o, I, I, 3, o, o, 3, i, o, i. 



44 ■ WILLIAM HOWARD BAT SON 

TABiLE VIII 
{Continued) 
Subject — D. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 

2, o, o, o, 3, o, o, o, I, 4, 4, 2, o, o, 3, 4, o, i, 2, 2, o, 

0, 5 ^ 122. 

Apr. 20. 3, 2, I, I, o, I, 4, I, I, 2, I, 3, I, — I, I, — I, 3, 2, 

4, I, 2, — 2, — 3, 2, — 2, O, O, O, O, 2, 3, I, 2, — 2, — ^2, O, — I, 

1, I, 2, 2, — I, — I, O, — I, — 2, O, — I, O, I, 3, 5, — 4, — I, — 4, 
— 3* — 2, O, O, — I, O, I, 2, — 2, — 3, — I, — I, I, O, — I, — I, 3, 
— 3, O, I, 2, — 3, — I, I, — 4, — 3, I, I, — I, — I, — I, O, — 2, O, 

1, O, O, 2, O, 2, O, O, O, 2, O = 142. 

Apr. 21. o, I, 3, o, o, 2, 3, 2, o, i, o, o, i, o, 2, o, i, o, i, 

3, O, — 2, O, I, O, — 2, 2, I, O, O, O, I, O, 5, O, O, O, — 2, — I, 
O, O, I, O, I, I, O, I, — 2, I, 4, O, O, O, — I, — I, o, o, o, 
O, 0, — I, o, 5, —6, O, 2, O, O, O, — 3, — I, — 2, O, — I, 2, o, o, 

— I, o, 2, 3, 3, o, o, o, o, — I, o, 0, o, I, — ^3, i, — i, — i, 

4, o, o, I, o = 95. 

Apr. 22. 2, — 2, — I, — s, 0, O, — 2, 3, O, 6, O, I, O, — 2, I, O, I, 

'i — 'f — 'i 'o 'o 'o 'z 'i 'o '£ 'z '£ 'o 'o 'o 'z 'i 'I 'i — 'z — 'i 

6, — 2, I, 2, I, 0, — I, — 3, O, 2, 2, 2, I, 2, 2, O, 2, — 2, I, 3, I, 
— I, 2, 2, O, O, — I, I, — I, 2, O, 0, — I, I, — 2, O, — I, 0, O, I, — I, 

2, O, — 2, O, O, — I, 2, — I, — ^I, 2, I, — I, O, — I, O, 3, O, — I, 0, 0, 2 == 122. 
Apr. 2S. 2, — 2, O, — 2, O, — 2, O, O, O', — 2, 3, O, 2, o, o, 4, 

O, O, O, O, 3, O, 2, I, I, O, O, 2, 2, O, 0, — I, O, O, — I, O, 2, 
O, O, 2, 2, 3, I, 2, O, O, O, 4, I, O, O, O, 3, O, 2, 2, — 3, 2, 

3, — I, I, I, I, o, o, o, I, o, Oj o, o, o, o, o, — ^3, 2, o, i, 3, 

4, 3, 2, O, O, O, — I, — I, — 2, O, — I, O, O, O, O, O, O, O, — 3, 2, o, o = 96. 

Apr. 24. — 3, — 2, o, — I, o, o, I, 2, I, o, 2, o, 2, 2, o, o, 2, 

—I, —2, 3, 3, —2, o, 3, o, o, —3, o, —3, 3, o, —2, 3, 3, 2, 

o, o, o, I, 4, o, o, — ^3, 3, I, o, o, o, 2, — 2, 3, i, 2, o, i, 

o, o, — 2, o, — 3, — I, I, o, — 2, o, 3, o, — 3, 4, o, o, 3, — i, — 2, 

— 2, — I, I, O, I, O, 2, 5, O, O, — I, 2, I, O, O, I, 4, o, o, o, 
— 2, O, I, O, O, — I = 124. 

Apr. 25. — I, o, o, o, 3, — I, o, o, 3, i, 4, o, 3, 3, 2, o, o, o, 

O, I, 2, 4, 4, O, I, — I, 2, — I, 2, I, O, 2, 2, — 3, O, — I, O, 2, O, 

0, 2, o, o, o, o, o, I, o, o, o, I, o, 3, 3, 4, 2, o, — i, i, 3, 

1, O, O, O, O, O, I, 2, O, — I, 2, I, O, 2, — I, O, O, 2, O, I, O, 
I, O, O, O, I, I, 2, 2, 3, I, O, O, O, I, 2, I, O, I, I = I02. 

Apr. 26. o, — 3, 2, o, o, — 2, o, o, o, 2, o, — 3, o, i, o, o, i, 

O, 2, O, 2, — 5, O, 0, O, O, O, — 2, — I, 2, — I, 4, — I, 0, — 2, 0, — 3, — 2, — I, 

o, o, — ^3, — I, o, o, o, o, o, o, — 3, o, o, — 2, o, o, — 3, o, 

0, 2, — I, 2, — I, I, O, — I, O, O, O, O, O, — 2, O, O, I, O, — 2, 

1, I, 2, O, — 2, 3, I, O, — 2, — I, O, — I, — I, O, 0, 2, O, O, O, 

0, O, O, — I, o = 84. 

Apr. 27. o, o, o, 2, 2, o, 3, — I, o, o, o, 2, 2, 7, — 2, — i, — 2, 

— 3, o, — 2, — 2, O, I, I, — 3, O, — 3, I, I, — I, — I, 2, O, — I, — I, 

O, 2, I, — 2, O, O, 0, — 2, — I, O, — I, I, O, — I, O, I, 4, 0, — 3, 

1, — I, 2, I, O, 2, O, O, 2, — I, 0, — 3, O, O, I, 3, O, O, — I, O, 

2, — I, — I, — ^I, O, O, I, 2, O, — 3, — I, I, — I, O, I, 0, O, 2, I, 

o, 2, o, 3, o, o, o = 107. 
:Apr. 28. 2, 3, 3, o, o, — i, i, o, 3, 2, o, o, o, — ^i, o, — 2, o, 

O, 2, O, O, — 2, 2, 2, O, 2, O, — I, O, 2, O, O, O, 2, O, — 2, 2, 
O, — 2, 3, O, O, O, — I, I, O, I, — S, 2, O, O, 3, O, — I, 2, I, 
— I, — 4, O, O, O, 2, O, O, O, O, O, — I, — I, O, O, O, — I, o> 2, 
O, O, O, I, O, O, O, 2, O, 3, O, 2, O, O, 2, — 2, — I, 2, — I, 
O, O, 2 = 89. 

lApr. 29. — I, — I, o, — I, o, o, I, 2, 4, I, o, o, o, o, 2, o, 

— ^I, O, O, — 4, O, O, I, I, O, O, I, — 2, 2, — I, O, O, I, — 2. 



ACQUISITION OF SKILL 45 

I 

TABLE VIII 
(^Continued) 
Subject — D. 

Experiment — To obtain a curve of learning for direction. Work consisted 
in rolling a steel ball at a mark. 

2, o, 2, o, 3, o, o, 2, I, 3, — I, o, o, — I, — 3, o, I, o, 2, I, 
— I, 3, 3, o, 2, o, 5, 3, I, o, — I, — I, o, —I, —I, o, o, 2, 
O, I, I, I, I, — I, o, o, — I, o, o, o, 4, I, 4, o, o, o, — 2, 

0, — 2), — 3, o, I, 2, 2, — I, o =z 104. 

Apr. 30. 3, 2, o, — 3, — ^i, 2, I, o, o, I, — 2, 5, o, 2, 3, o, o, 

1, — 4, — ^i, — I, — 2, o, — 2, — I, 2, o, I, 2, — I, — I, o, I, o, 
I, — I, 2, 2, o, o, o, I, o, o, 2, o, I, 2, o, — I, — I, 5, 2, o, 

— 3, 2, O, O, — I, O, O, O, — I, O, O, — 2, O, O, — I, O, O, — 2, 
I, O, 3, 5, 2, I, O, O, O, O, — 2, O, O, I, O, O, O, O, — I, — I, 

0, O, I, I, 2, 2, 3, O = 104. 

May I. 2, o, 2, o, o, i, 2, i, — 2, — 2, i, o, i, 2, o, 3, o, o, 

3, —3, —3, 2, —2, —3, o, I, —I, 2, —3, —I, I, o, o, I, —3, — i, 

1, o, I, I, o, 2, I, 4, o, o, I, — 3, o, I, 4, o, o, o, o, 
— I, 0, o, o, o, o, o, I, 4, — I, — I, I, o, I, o, 7, o, 0, — 3, 

1, O, 2, — I, 5, O, I, O, I, O, I, O, 2, O, O, I, O, O, I, o, 

o, o, o, I, o = 105. 
'May 2. o, o, — I, o, I, 5, I, 2, o, 0, I, 0, o, 2, o, i, o, — i, 

O, O, — I, O, O, O, O, O, I, I, O, O, O, 2, 2, I, O, O, — I, 

2, O, O, I, 2, — I, O, 3, I, O, 2, — I, — ^^I, — 2, O, O, I, — I, O, 
' — I, O, O, O, 2, I, — 2, 2, 2, O, O, I, O, 2, O, O, O, O, O, O, 

o, o, o, o, o, 3, — I, — I, o, 3, o, — I, o, 2, o, 3, — 3, 4, 3, 
— I, O, I, O, I = 82. 

May 3. — 2, 4, o, 5, 3, i, i, — i, — 2, o, o, 2, i, o, — 2, o, o, 

' — 2>, I, o, o, I, — I, — r, o, o, o, o, I, — I, o, 2, 3, i, 3, 2, o, 

3, — I, o, o, o, 2, o, o, 2, o, o, — ^i, 3, 4, 3, o, o, 2, 3, i, 

O, I, O, O, O, 2, O, O, O, — 3, I, O, — 3, O, I, 0, O, I, o, o, 
O, 3, I, — 3, I, O, I, 2, I, O, 0, O, — 2, 2, 2, O, 2, 4, O, — 2 = IO7. 

'Miay 4. o, I, 2, 2, 2, 2, — I, — I, 0, o, o, — i, 3, 0, 3, 3, o, — i, 

O, — 2, O, O, 2, O, — 4, O, 2, O, 5, — 4, O, O, 2, O, O, — I, 2, I, 
O, — 2, O, — 2, O, — I, O, O, — 2, O, — I, O, — I, — I, 0, — I, O, O, 

o. o, 7, — 2, — 5, — 3, — 5, 0, o, o, o, o, — i, 0, o, — i, 2, — 2, o, 

— 2, 4, I, — I, 2, I, 2, I, 3, I, 2, O, O, O, O, — I, I, 0, I, 2, 2, 
— 2, I, O = Il6. 

May 5. o, I, 3, 5, o, o, o, o, 2, o, o, 0, 2, o, i, 2, i, i, — r, 

3, 2, O, I, O, O, I, O, O, I, O, I, — I, 0, O, 2, O, O, 3, o, 

O, I, O, 2, O, 0, 0, O, — 2, O, O, O, O, 1, O, 5, 2, — I, 3, 2, O, 

O, O, O, O, — 2, I, 2, 2, O, O, O, I, 3, O, O, I, — I, I, I, O, 

0, I, o, o, I, o, I, o, — I, o, 4, — I, 2, o, I, o, o, — I, 2 = 83. 
May 6. 3, 2, — 2, o, o, o, — 2, o, o, o, — i, 3, o, o, — 2, i, 

3, O, O, I, O, I, O, O, 2, I, — 2, 2, I, O, I, 4, I, O, I, o, 

1, O, O, 2, 0, O, I, 2, O, 2, 2, I, 3, — I, — I, O, I, 0, O, 
I> — 2, — ^2, 3, I, I, 3, — I, 4, 2, O, 2, I, — 2, O, O, I, O, 

— I, 2, — 2, I, 2, O, O, — I, O, O, O, O, O, O, 2, I, — I, 2, — 2, O, 

1, I, 3, o, o, I, —3 = 105. 

'May 7. I, I, I, o, o, — i, — 2, o, o, o, — 3, o, i, o, o, o, o, 

— I, O, — I, — I, 2, I, — I, — 3, O, — 2, O, O, O, O, 2, 0, O, O, 

2, 0, O, — I, O, — 2, 0, 2, O, Oj — 2, O, O, O, — I, O, — I, 
— I, o, — I, O, O, — 2, 0, 2, o, o, o, O, O, — I, — I, — I, 3, o, 

— I, O, O, O, O, 1, I, 0, 2, 2, O, I, O, O, I, O, — 2, O, — 2, 

— ■!, O, O, O, — I, O, — I, = 64. 

May 8. 2, o, i, o, o, o, — i, — 2, 3, 0, o, o, — i, 2, — i, 

2, O, 3, O, I, 2, 3, — 2, I, I, O, O, — I, O, — ^4, O, O, O, — I, 
— I, — I, — I, O, O, — I, — I, O, O, — 2, O, — I, O, — I, 2, 2, O, 
2, — 2, O, — I, 2, O, O, I, O, I, I, O, 2, O, O, I, O, — I, O, O, 



46 WILLIAM HOWARD BATSON 

TABLE VIII 
{Continued) 
Subject — D. 
Experiment— To obtain a curve of learning for direction. Work consisted 

in rolling a steel ball at a mark. 
3^ o, —2, —2, o, o, o, o, —2, —I, 4, o, o, 3, o, o, o, o, o, 
o, — I, — I, o, o, o, 3, — 2, I, o = 86. 

(May g. 4, 2, — i, o, — i, — i, — i, — i, 0, —2, i, — i, o, — i, 
o, 2, 2, o, 2, o, o, o, o, o, 2, o, o, 3, I, o, o, I, o, I, 
o, I, — 2, —I, — I, —I, 2, I, I, 0, 0, I, — I, o, o, — ^i, 2, o, 2, 2, 
o, 4, O, O, O, — I, o, o, o, 0, 2, o, 2, O, I, I, 0, 4, o, o, 

0, 2, O, 4, O, I, O, —I, O, O, O, O, I, —I, o, O, O, 3, I, o, 

1, O, I, I, o, o = 81. 

May ID. 3, o, —I, 2, —I, o, o, 2, 2, 2, — i, 2, o, —3, 2, o, 

O, — I, o, O, — I, O, O, O, O, O, 3, O, — I, O, O, — I, — '2, 2, O, 

O, 2, — I, I, — I, O, O, O, O, — I, 0', o, o, o, o, o, o, o, o, o, 

— I, O, O, 0, — I, O, O, O, O, I, — I, I, I, O, O, I, O, 3, O, 2, 

O, O, O, 0, I, 0, O, O, O, O, O, O, 2, 3, 0, O, — 4, — I, 2, — I, 

o, o, o, — I, I = 66. 
May II. I, 0, o, — i, o, o, o, 2, i, 2, i, — i, o, 0, 3, o, o, o, 

0, O, I, O, O, I, O, O, O, O, O, 2, 2, O, — I, I, O, — I, O, O, 
— 2, 2, 2, — I, O, O, — 2, O, O, — 2, O, O, O, I, O, O, 2, — I, O, 

0, — I, — I, O, O, 2, O, O, O, I, I, I, O, O, O, I, o, o, o, o, 

1, 2, 2, I, — 3, — 2, — I, 0, — 2, 2, O, O, O, I, 2, O, O, O, O, 
O, O, I = 64. 

May 12. o, I, 0, i, o, o, 3, 0, i, 2, o, o, 2, o, o, o, o, — i, 

— 2, O, O, I, O, O, I, O, O, O, O, O, O, I, O, O, O, O, O, — I, 

O, 2, G, — I, I, O, O, O, I, O, O, O, O, O, — 2, O, O, O, 0, O, 

O, O, O, I, — 2, — I, O, O, O, O, O, O, O, O, 2, O, O, O, O, O, 

2, O, O, O, O, O, I, O, O, O, O, O, 0, 0, — 2, o, o, o, o, o, o, o = 35. 

May 13. o, o, — i, o, o, o, 2, o, i, 3, 2, i, o, 2, — i, o, — i, 

0, I, O, O, O, O, O, O, O, O, 0, O, O, O, O, O, O, 0, I, I, 

1, I, O, O, O, O, 0, O, O, O, O, I, I, I, I, O, O, O, I, 2, 
O, O, 0, O, O, O, O, O, I, O, — I, — I, O, O, O, I, O, — I, I, 
O, O, O, 0, — I, I, O, O, — I, O, — I, O, O, I, 2, — I, — I, — I, 
O, — I, — I, I, I, o = 46. 

May 14. I, o, o, I, o, — I, — I, o, o, — 3, o, i, i, o, o, i, — i, 

O, O, O, O, 2, O, O, — I, I, O, 2, O, O, I, 2, O, O, I, I, O 
O, O, O, O, O, — I, — I, O, 2, O, — I, I, O, I, I, — I, 3, O, I, I, 

2, O, O, I, — I, O, O, O, O, O, O, O, I, I, 2, O, O, O, O, I, 

— I, — 3, o, 0, o, I, o, o, I, o, o, o, o, 0, 5, o, o, o, i, 

0, I, O, = 58. 

May 15. o, o, o, o, o, o, o, i, o, 2, i, 2, — i, — i, o, o, o, 

1, I, I, I, I, — I, 2, I, — I, O, O, 0, I, O, O, O, 0, 0, O, I, 
I, O O, O, I, O, O, O, O, I, 2, O, O, O, O, O, I, 3, I, 3, o 
O, I, I, 4, I, — I, — 2, O, O, — I, O, 0, O, O, I, 0, 2, 2, 2, 

0, O, O, I, O, 2, O, O, — 2, — 2, O, I, O, 2, I, O, O, O, 0, 0, — 2, 

—I, o — 65. 

May 16. I, o, o, o, i, — 2, 3, 4, 2, — 2, o, i, — 2, o, i, 2, 

1, O, 4, I, O, O, O, 2, I, 2, O, O, — I, — 2, I, 3, O, 2, O, O, 
I, O, 2, 0, O, I, O, O, O, O, O, O, I, O, I, I, — I, I, O, O, I, 

1, 3, I, — I, — I, 2, — I, O, O, I, I, I, I, I, O, I, — I, I, 0, — I, 

2, O, O, 2, O. 2, O, — I, O, O, O, O, — I, O, I, 3, 0, — I, O, 2, I, 

3 = 89. 
May 17. o, o, i, 2, o, o, o, o, — i, o, i, o, 2, 3, o, i, o, o, u 

O, O, I, O, O, O, O, O, O, I, O, O, O, I, I, I, O, O, O, O, I, o. 
O, I, 0, O, O, O, O, 0, O, O, I, — I, O, I, — iJ, O, I, o, O, — I, 
O, O, O, 2, O, 0, O, — I, — I, — I, o, O, O, O, I, O, 0, o, o, o, o, 
o, I, o, o, o, o, o, I, I, — I, o, o, o, o, o, I, o = 35. 

May 18. 2, 2, o, o, o, — i, — i, o, o, o, o, o, o, o. o, i, i. 



0, 


I, 


I, o, 


I, 


0, 


0, - 


0, 


0, 


0, o, 


0, 





= 40 



0, 0, 


0, 


0, 


0, 0, 


0, 


I, 


0, 0, 


0, 


0, 


0, 0, 


I, 


I, 


0, 0, 


0, 


0. 


, — I, - 


—2 


0, 


0, 0, 


0, 


0, 


I, 0, 0, 


, - 


—I, 



ACQUISITION OF SKILL 47 

TABLE VIII 

Subject — D. 

Experiment — To obtain a curve of learning for direction. Work consisted 

in rolling a steel ball at a mark. 
o, 3, o, o, 2, o, 0, o, 2, I, o, o, o, — I, o, o, o, — I, 0, o, 2, 
o, o, o, o, 3, o, o, o, o, o, o, I, o, I, I, — I, I, — I, o, 
O, O, O, I, O, O, O, O, O, I, O, — I, I, O, O, I, O, O, I, o, o, 
O, O, — I, O ,1, 2, 2, O, O, 0, O, O, O, O, O, O, O, O, O, O, O, O = 4I. 

May 19. I, I, I, 0, — I, o, o, — i, o, o, o, — 2, — i, o, o, o, o, i, 

O, O, — I, I, 2, O, O, I, O, O, O, 0, O, — I, — I, O, O, O, O, 0, 

O, I, O, O, I, I, O, 2, 2, 0, O, I, O, 0, I, O, O, I, O, O, O, 

0, O, I, O, O, O, O, O, I, O, 2, O, O, I, O, O, I, O, — 2, I, 0, 

1, O, O, O, O, O, O, O, I, O, O, O, — I, o, o, o, o, o, o = 38. 
May 21. — 2, — I, 0, o, o, — i, — 2, o, o, i, o, — i, o, o, 3, i, 

I, O, O, O, 0, O, O, — I, I, 2, 2, O, O, O, O, O, 0, O, O, O, O, 
— I, O, O, O, — I, I, O, O, O, — I, O, O, O, 0, o, 

1, O, O, O, O, O, O, 0, O, O, O, I, O, O, I, o, o, 
O, O, O, I, I, — I, O, O, O, O, O, O, 0, o, o, 

— I, I, o, o = 32. 

May 22. o, 2, o, 3, o, o, o, i, o, i, o, — i, o, 

2, O, I, O, O, I, O, O, O, O, O, O, O, I, o, o, 
O, — I, O, I, — 2, O, O, O, I, O, 4, o, o, o, 

2, 0, O, O, I, O, O, O, 0, O, I, O, 0, 
O, 0, O, O, — I, — I, O, I, o, o, o, — 



Curves XVI and XVII (Plate IV) are obtained by letting the 
total score for each day's practice represent divisions on the 
y-axis and practice periods represent divisions on the x-axis. 

Curves were also plotted representing the improvement meas- 
ured in terms of actual hits. The total number of hits made in 
each day's practice was taken as a basis for divisions on the y- 
axis and the number of practice periods as the basis for divisions 
on the X-axis. Curve XVIa (Plate VIII) shows the typical form. 

The two subjects were very different in their manner of throw- 
ing. Subject W., after a few days practice, threw the steel ball 
so that it curved from right to left. He used only enough force 
to enable the ball to reach the mark. He aimed at a mark on 
the board about eight inches from where he released the ball. 
After he had this plan perfected, it made no difference if a piece 
of card-board was set up between him and the block of wood in 
such a way as to shut off the view entirely. 

Subject D. threw directly at the mark. The ball rolled straight 
for the most part and with considerable force. Notwithstanding 
the difference in their method of practice, the curves show con- 
siderable similarity in the form of the improvement. Although 



48 WILLIAM HOWARD BAT SON 

the daily fluctuations are quite large, there is an almost constant 
downward course to each curve. The large fluctuations from 
the thirteenth to the twenty-first practice of Curve XVI repre- 
sent the period when the subject was attempting to curve the ball 
and to locate a place on the board near his hand through which 
he could throw the ball. It will be noted that at only one place 
are there as many as four consecutive points on the same side 
of the line passed from point seventy on the y-axis to point 
thirty-six on the x-axis of Curve XVI. With the exception 
of the period when the subject was attempting to find a new 
method, the curve follows the general direction of this line. The 
average deviation of the points from this line is eight. The 
upper heavy line shows the position where the plus and minus 
deviations are balanced. The sum of the deviations above this 
line is equal to the sum of the deviations below the line. The 
two dotted lines show the average deviation from the line. 

The course of Curve XVII is fairly well shown by a line 
drawn from 135 on the y-axis to a point 37 units above 35 on 
the X-axis. There is a period from the thirteenth to the twen- 
tieth practice when the score was rather high which was the 
result of the subject trying to spin the ball on its axis. The 
only explanation for the rise at the thirtieth and thirty-first 
practices was the bad weather which may have affected the sub- 
ject. Only in one case here do as many as four consecutive 
points remain on the same side of the line and three of these 
are within the average deviation limit, which is twelve in this 
case and is represented by the two dotted lines. 

An examination of Tables VII and VIII shows that the sub- 
jects were able to do almost equally well in each half of a prac- 
tice period. The scores that Subject W. made in the first half 
of his daily practices were as follows : 

50, 2,2, 31, 20, 24, 24, 44, 31, 22, 19, 27, 19, 22, 2>7, 31, 19, 17, 25, 28, 30, 13, 
g, 12, 24, 12, 16, 20, 6, II, I, 4, 4, 12, 8, 9, 5. Total 619. 

The scores for the last half of each practice were : 

40, 30, 42, 24, 25, 23, 21, 21, 26, 27, 29, 24, 29, 28, 26, 25, 15, 21, 28, 12, 17, 

4, 6, 4, 2, 6, 16, 10, 2, 4, 5, 5, o, I, I, 2, 7. Total 608. 



ACQUISITION OF SKILL 49 

The scores for the first half of each practice for Subject D. 
were: 

33, 79, 63, 71, 48, 71, 49, 67, S3, 49, 58, 47, S8, 64, 38, 56, 55, 39, 5i, 34, 47, 
43, 2>^, 32, 22, 21, 28, 25, 46, 18, 24, 24, 23, 22, Total 1496. 

The scores for the last half of each practice were : 

71, 46, 59, 71, 47, 51, 47, 57, 49, 35, 49, 2,7, 57, 46, 41, 44, 5i, 61, 44, 54, 30, 39, 
38, 2S, 32, 13, 25, 30, 40, 43, 17, 17, 14, 9, 18. Total 1410. 

On July 17, 1914 Subject W. was tested again in this work. 
The only difference was that the board this time was covered 
with heavy paper. He had had no practice since May 18, 19 13. 
This practice consisted of a hundred trials. The result was : 

First fifty. — i, 4, 5, 4, 7, o, o, o, 3, o, i, o, 6, 3, o, o, o, o, o, 
o, o, o, o, 2, 0, o, o, o, o, o, 3, o, I, o, — 2, o, — 2, I, 2, 
o, o, o, 4, o, o, I, o, o, o, o. Total 52. 

Second fifty, o, o, o, o, o, 2, o, o, o, o, 5, o, o, o, o, o, o, 
o, o, o, o, o, o, o, o, o, o, o, 5, o, o, o, o, o, o, 4, o, o, 
o, o, o, o, o, o, o, o, o, o, o, o. Total 16. 

The subject explained his difficulty in the beginning by the 
fact that the ball would not curve on the paper as it had done 
on the board. The second fifty shows how fast he was able to 
adapt his method to the covered board and then his work was 
nearly as good as it had been at the end of the practice. 

In order to give an idea of the amount of skill that had been 
acquired by the above subject a comparison practice was given 
Subject Do. (Dockeray) on the same day as the above practice 
and the following score was made : 

2, o, 6, o, 5, —2, —4, I, o, 5, 4, 2, o, 4, 3, I, I, 3, 5, 6, o, 
—5, —^, 7, I, —5, 6, 5, —I, I, —7, —2, o, 5, 6, 5, — i, i, —7, 
— 2, o, 5, 6, 5, — I, I, — I, — 2, I, 5. Total 154. 

This is a considerably higher score than either of the other two 
subjects made in their first practice but it indicates that the 
putting on of the paper had not made the work easier. 

Experiment II. On Force 
Four subjects took part in this experiment : Subject W. 
(Wang), Subject D. (Decamp), Subject C. (Cole), and Sub- 
ject Do. (Dockeray). The last two were also graduate students 



so WILLIAM HOWARD BATS ON 

in psychology. The apparatus for Subject W. was the same as 
in the preceding experiment, except the block of v*^ood was not 
used and instead of the steel ball, two rubber balls that lir.d 
been used in the ball tossing experiments were used. The board 
was placed on a table with a point marked zero three and one half 
inches above the mark from which the ball was thrown. There 
was a space of seven and one half feet on the board between these 
two marks. At the zero mark a heavy line was drawn across the 
board. On either side of this line divisions were laid off three 
inches wide by other lines drawn across the board parallel to the 
line running through the zero mark. These divisions ran up to 
plus thirteen on one side of the zero mark and to minus thirteen 
on the other side of the zero mark. The mark from which the 
ball was thrown was drawn across the board parallel to the line 
drawn through the zero mark and was, as stated above, seven 
and one half feet from it. 

The second board which was used with the other three sub- 
jects was covered with a piece of heavy paper during the latter 
part of the practice. It was laid off in the same way as the one 
above except the divisions ran up to plus fifteen on one side and 
to minus fifteen on the other side. The minus numbers in both 
cases were next to the subject. In this case the steel ball was 
used instead of the rubber balls. 

The subject in both cases stood at the lower mark and at- 
tempted to throw the ball so that it would roll to the zero mark. 
He was instructed not to let his hand pass the lower mark. The 
subjects that shot the steel ball as one would a marble with the 
thumb put the fore finger down on the mark and did not move 
it when the ball was released. If the ball went beyond the zero 
mark the division in which it stopped was noted as "-|-8" etc., 
or if it did not reach the zero mark the division was indicated 
as "—7" etc. 

The results of this experiment are shown in Tables IX, X, XT. 
and XII. The first horizontal column of figures shows the days 
on which the practices were taken. The first vertical column 
represents the divisions on the board. The columns to the right 
of this show the distribution of each fifty throws. Commencing 



ACQUISITION OF SKILL 51 

at the top of the first practice period (Feb. i) of Subject W., 
it is seen that the ball stopped twice in the plus thirteen division, 
twice in the plus eleven division, etc. The score is found by 
multiplying the numbers in the first vertical column by the num- 
bers that stand opposite to them in the practice columns and tak- 
ing the sums of these products. 

Subject W. commenced work on Feb. i, 191 3 and continued 
until Feb. 20, 191 3. Subjects D. and Do. commenced on June 
29, 1 91 4 and Subject C. on June 30, 191 4. All three of these 
subjects continued practice until July 19, 1914. 

In this work, Subject W. and Subject C. used a full swing of 
the arm to throw the ball. Subject D. and Subject Do. used only 
the thumb to propel the ball. The curves for these results are 
plotted by using the number of spaces that the mark is missed 
for the divisions on the y-axis and the practice periods for the 
divisions on the x-axis. Curves XVIII, XIX (Plate V), XX, 
and XXI (Plate VI) show the general trend of this learning. 
Curves XVIII and XIX show a marked drop at first and then a 
more gradual fall with wide fluctuations. Curve XX shows a 
relatively low score during the third and fourth practices and 
then a rise which lasted for several days. This was caused by 
putting paper on the board which made the ball roll more easily. 
It appeared to bother this subject much more than the others. 
On the twelfth day he found that he could judge the force much 
better when he let his finger drag along lightly on the paper. 
After that his score continued to be much lower. 

The curves may be compared by passing a line through them 
so as to leave as nearly as possible the same number of points on 
either side of the line and at the same time have as few con- 
secutive points on either side of the line as possible. In Curve 
XVIII, a line drawn from ninety on the y-axis to a point seventy 
units above the twenty one on the x-axis leaves ten points on 
either side of it with not more than three consecutive points in 
one place. The sum of the deviations of the plus units is 115 + 
and that of the minus units is I02-|-. The average deviation 
from this line is 10.9 and is represented by the dotted lines. 

In Curve XIX, a line drawn from one hundred and eighteen 






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S6 WILLIAM HOWARD BAT SON 

on the y-axis to a point sixty eight units above twenty one on the 
X-axis leaves eleven points above and ten below with not more 
than four consecutive points on either side. The sum of the plus 
deviations is 144+ and the sum of the minus deviations is 131 +. 
The average deviation is 13.3. 

Curve XX does not yield to this method of treatment very 
well, partly for the reason mentioned in the preceding page. No 
line can be drawn through the curve in such a way as not to leave 
several consecutive points on one side. A line drawn as indicated 
from one hundred and twenty on the y-axis to forty units above 
twenty one on the x-axis shows its general direction about as 
well as any one line will do. This line leaves ten points above 
and ten below. The sum of the plus deviations is \ii-\- and the 
sum of the minus deviations is 109-j-. The average deviation 
is II. 

The direction of Curve XXI is indicated by a line drawn from 
eighty three on the y-axis to a point forty eight units above 
twenty one on the x-axis. This line leaves ten points above and 
eleven below. There are not more than three consecutive points 
on either side. The sum of the plus deviations is 84-f- and the 
sum of the minus deviations is 88+. The average deviation 
is 8.6. 

If the slope of the line is taken to represent the improvement 
it is seen that Curve XX stands first with a slope of .80. Curves 
XIX, XXI, and XVIII have respectively .50, .35, and .20. 

For the purpose of comparison curves were drawn which rep- 
resented a range of +1 to — i on the board. For instance in 
Table IX on the first trial the ball stopped eight times on -|-i, o, 
and — I. The sum of these three divisions was taken each trial 
for divisions on the y-axis and the number of trials for divisions 
on the X-axis. Curves XXa and XXIa show the general form 
of the curves obtained by this method. 

It would seem in this experiment that the person who is able 
to make a low score would be the one who is able to perceive ac- 
curately small amounts of force. It would require the same kind 
of ability as distinguishing small differences in weights. In 
order to test this, three subjects (Subjects D., Do., and C.) 



ACQUISITION OF SKILL 57 

were tested for their ability to distinguish small differences in 
the weights of bodies. Eight weights were used for the test. 
Hollow hard rubber cylinders were used for this purpose and 
loaded with shot and felt so that they weighed 75.001, 76.004 
77.002, 78.001, 78.996, 79.998, 85.004, 90.005 grams respectively. 
The weights were numbered from one to eight. They were 
presented to the subjects in pairs. The subject was blindfolded 
and required to lift the cylinders two inches from the table or 
until they touched a rod running horizontally. The subject re- 
ported the last weight as heavier or lighter. 
The tables below show the result of the test : 

Weights in order i — 8 i — 7 i — 6 i — 5 i — 4 i — 3 i — 2 

Subject C. — Right 10 9 10 10 10 9 6 

— Wrong I 14 

Weights in order 8—1 7 — i 6 — i 5 — i 4 — i 3 — i 2 — i 

Subject C. — ^Right 10 9 8 5 4 4 5 

— Wrong I 2 5 6 6 5 

This shows that the subject gave 109 right judgments and 31 wrong ones 
or he obtained a percentage of 77.8 correct. 

Weights in order i — 8 i — 7 i — 6 i — 5 i — 4. i — 3 i — 2 

Subject Do. — ^^Right 10 9 5 10 7 8 7 

—Wrong I 5 3 2 3 

Weights in order 8 — i 7 — i 6 — i 5 — i 4 — i 3 — i 2 — i 

Subject Do. —Right 8 8 8 8 7 6 6 

— Wrong 2 2 2 2 3 4 4 

This shows that the subject gave 107 right judgments and 33 wrong ones 
or he obtained a percentage of 76.4 correct. 

Weights in order i — 8 i — 7 i — 6 1—5 i — 4 i — 3 i — 2 

Subject D. — Right 10 8 7 9 9 9 6 

— ^Wrong 2 3 I I I 4 

Weights in order 8 — i 7 — i 6 — i 5 — i 4 — i 3 — i 2 — i 

Subject D. — Right 10 8 7 2 3 5 4 

—Wrong 2 3 8 7 5 6 

This sihows that the subject made 97 right judgments and 43 wrong ones 
or he obtained a percentage of 69. correct. 

If these figures are compared with those representing the slope 
of the lines on the curves, it is seen that the subject that showed 
the greatest improvement in the force test has the largest per- 
centage of correct judgments of weight and that the other two 
follow in order. 



S8 WILLIAM HOWARD BATS ON 



Experiment III. On Time 

Subjects W., B., C, and D. took part in this experiment. The 
apparatus consisted of a circular piece of board about twelve 
inches in diameter and three quarters of an inch thick, placed in 
a vertical plane on an axis. Beneath the board v^as a pulley so 
that a motor could be attached and the board rotated. Two 
circular bands of cardboard were made by bending strips into 
the form of a hoop. These two bands were placed on the board, 
the one inside of the other. The inner band was one and one 
half inches in height and nine and five eights inches in diameter. 
The outer band was one and one half inches outside of the inner 
band and was one half inch high. The space between the two 
bands of cardboard was divided into twelve parts by tacking 
pieces of tin on the radii of the circular board. These pieces of 
tin were the same height as the outside band of cardboard. 

A trough about twenty inches long was supported so that the 
lower end rested one half inch above the little pockets on the 
circular board. The other end of the trough was six and one 
half inches higher. The trough was made by nailing two pieces 
of wood together at right angles and then it was lined with soft 
tin so that it was perfectly smooth. A mark was made in the 
trough eighteen inches from the lower end. On this mark the 
subject held a piece of wood that fit the bottom of the trough and 
behind this was placed an ordinary B.B. shot. When the subject 
lifted the piece of wood the shot rolled down the trough and 
fell into one of the pockets on the circular board. 

One of these pockets was marked by placing a piece of green 
paper in the bottom of it. The circular board was covered with a 
piece of cardboard from which a sector had been cut so that only 
a small part of the circular board was visible beneath the end of 
the trough. As the board rotated, the subject could see the 
pockets pass under the end of the trough and then disappear 
under the cardboard. The object was to release the shot so that 
they would roll down the trough in time to fall into the marked 
pocket. The circular board was rotated forty six times per 



ACQUISITION OF SKILL 59 

minute or a pocket passed the end of the trough in one ninth of 
a second. The movement of the board made it impossible to 
distinguish any of the pockets except the one that had the green 
paper in it. The subject waited a short time after the marked 
pocket had passed the end of the trough and then released the 
shot. The aim was to improve his ability, to judge this period 
of time. 

The subject could see the shot hit the pocket if they hit near 
the middle but if they hit near the side of the pocket he was not 
able to tell if they hit too early or too late. The pockets were 
marked zero, one, minus one etc. out in either direction. The 
score was kept by counting the number of shot in each pocket. 
These numbers were multiplied by the number of the pocket and 
then the sum of these products taken for the daily score. 

Subject W. commenced this work on May 13, 191 3 and con- 
tinued it until May 24, 191 3. The practice consisted of fifty 
trials daily. The result of his work is shown in Table XIII. 

Subjects B., C, and D. commenced work on June 30, 1914 
and continued until July 19, 191 4. The practice was daily and 
consisted of fifty trials. The results are shown in Tables XIV, 
XV, and XVI. 

Curves XXII, XXIII (Plate IV), XXIV and XXV (Plate 
VI) show the form of the improvement. All the curves show 
rather a large drop during the first two or three practices. After 
that there is a slow but gradual improvement to the end of the 
practice. The first large drop in each case is the result of the 
subject's learning the apparatus. He would have a few very 
bad results at first which would not occur again after a few 
trials. Curve XXIII does not show this first early drop to so 
great an extent because the subject had set up the apparatus and 
knew by a few trials previous to the first test what to expect. 

The direction of these curves after the first two or three prac- 
tices is shown by the straight lines drawn through them. A 
line run from forty one on the y-axis to seventeen units above 
thirteen on the x-axis of Curve XXII shows that with the ex- 
ception of the first two practices the points alternate on either 
side of the line. The sum of the plus deviations is 10 and the 



6o WILLIAM HOWARD BATS ON 

sum of the minus deviations is 15. The average deviation is 2.5. 

On Curve XXIII, a line run from thirty five on the y-axis to 
fifteen units above twenty one on the x-axis leaves not more 
than two consecutive points on either side. Omitting the first 
practice, the sum of the plus deviations is 35 and the sum of the 
minus deviations is 36. The average deviation is 3.5. 

On Curve XXIV, a line run from forty three on the y-axis to 
twenty nine units above twenty one on the x-axis leaves no more 
than two consecutive points on either side of the line. The sum 
of the plus deviations is 29.4 and the sum of the minus devia- 
tions is 33. The average deviation is 3.2. 

On Curve XXV, a hne run from thirty four on the y-axis to 
a point eighteen units above twenty one on the x-axis leaves no 
more than three consecutive points on the same side of the line. 
The sum of the plus deviations omitting the first one, is 41.8 and 
the sum of the minus deviations is 41.7. The average devia- 
tion is 4.1. The slope of these lines is .40, .20, .14 and .16 for 
the curves taken in order. 

When the actual number of hits, that is the number of shot 
that went into the marked pocket was taken to represent divisions 
on the y-axis and the trials to represent divisions on the x-axis, 
the curves take the form represented by Curves XXIVa and 

XXVa (Plate VII). 

TABLE XIII 

Subject W. 

(Experiment — To obtain a curve for learning to judge time. The first horizontal 
column represents the number of practice days. The first vertical col- 
umn to the left shows the number of the pockets. The other vertical 
columns to the right show the distribution of the fifty shot in each prac- 
tice. The number at the foot of each vertical column shows the total 
score. 

May 13 14 15 16 17 18 19 20 21 22 23 24 



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ACQUISITION OF SKILL 63 

An examination of all these curves where a single element is 
involved shows that there is a large degree of similarity in them. 
All three of the experiments were such that it was hardly possi- 
ble to reach and maintain the limit of perfection. Except in the 
cases where the subjects made very high scores during the first 
two or three practices, the curves show a downward slope with 
considerable daily fluctuations. These daily fluctuations balance 
each other in almost every case within four or five days. 

It is likely that if the practice had been continued until the sub- 
jects had reached a point where they were no longer able to 
distinguish the selective element as force or time, the curves 
would have approached parallelism with the x-axis. 

In the ball tossing experiments the work was such that a 
number of elements had to be improved together or the unit of 
measure did not indicate the advance. In the second set of ex- 
periments where the elements of direction, force and time are 
involved a relatively simple reaction was required. The next 
set of experiments are such that a number of elements are in- 
volved but in such a way that the attention may be focused on 
any one of them or distributed over the whole of them. 



THE EFFECT OF SEVERAL FACTORS 
WORKING IN SUCCESSION 

The ball-tossing experiments showed the nature of the curves 
of learning when several factors must be attended simultan- 
eously. The experiments on the judgment of direction, force, 
and time showed the form of the curves of improvement when 
the attention is centered on a single factor. It is the purpose 
of the following experiments to show what form the curves of 
learning take when several factors influence the attention but in 
such a way that they can be considered separately. 

Four subjects — M. (Martin), Fe. (Feemster), S. (Miss 
Scott), Cd. (Miss Coldwell) took part in the work. They were 
all undergraduates in college. 

The apparatus (See Fig. i) consisted of a disk ten inches in 
diameter cut from a pine board three quarters of an inch thick. 
This disk was placed in a horizontal plane on an axis. The axis 
ran through and was fastened beneath a table. Beneath the disk 
was a pulley by which a motor could be attached. On top of the 
disk, eight holes had been scooped out similar in form to the 
bottom of a spoon. These holes were three quarters of an inch 
in length, one half of an inch wide and one fourth of an inch 
deep. They were located three quarters of an inch from the 
circumference of the disk and extended across the ends of four 
diameters that divided the disk into eight equal parts. A piece 
of cardboard covered three fourths of the disk leaving one 
fourth in the form of a sector exposed. The top of the disk 
was three inches from the table. 

A frame was set up twenty-three inches from the center of 
the disk. This frame was perpendicular to the table and was in 
a plane parallel to the radius that divided the exposed sector of 
the disk into two equal parts. The frame was sixteen inches 
square and inclosed a hoop that just touched the sides. A piece 
of cloth was spread over this hoop and sewed to the hoop all 




fc 



ACQUISITION OF SKILL 63 

the way around the border. At the center a circular piece of 
wire was inserted which was four inches in diameter. A piece 
of cloth was sewed to this wire ring in such a way as to leave 
a pocket extending out on the side opposite to the disk. The 
center of this pocket was eight inches from the table and about 
five inches above the level of the top of the disk. 

The subject held in his right hand a pair of tongs nine inches 
long which were bent down at right angles one inch from the 
lower end. The seizing end of the tongs was one eighth of an 
inch wide and was ground perfectly smooth. 

The work of the subjects was to take these tongs and seize 
shot from the eight holes on the disk and throw them into the 
four inch pocket in the middle of the circular hoop twenty-four 
inches to the right. The disk was rotated eleven times per 
minute by means of a motor. This made the shot pass the point 
where they were to be seized at the rate of eighty-eight per 
minute. After the subject had struck at the shot during one 
revolution of the disk, he rested until it was refilled. The sub- 
ject was instructed to strike at every shot that appeared and to 
throw as many of those that he seized into the pocket as possible. 

In taking the data, four things were considered : First, the 
hitting the shot; second, the seizing the shot; third, the hitting 
the large circle which included all of the area of the hoop which 
was sixteen inches in diameter; fourth, the hitting the pocket. 
The practice consisted of eighty strokes at shot, taken daily, 
except as noted in the tables. The practice of all the subjects 
was in the afternoon between twelve-thirty and one-thirty o'clock. 

Subject M. commenced this work on Jan. 20, 191 4 and con- 
tinued it until June 5, 191 4. He was given a certain position in 
which to stand, that is on a certain side of the table, and was told 
to strike at every shot as it appeared with the aim of seizing it 
and throwing it into the pocket. The importance of striking 
every shot was emphasized and at the end of eight strokes he 
was required to make a stroke at the hole in which he had struck 
at the first shot. This was done so that he could not take extra 
time to throw the last shot. 

The result of his work is shown in Table XVII. Curve XXVI 



66 WILLIAM HOWARD BATS ON 

(Plate V) is plotted from these figures. The spaces on the y- 
axis represent the number of shot. The spaces on the x-axis 
show the number of practice periods. The part at the top shows 
the number of shot hit; the next cne below it, the number of 
shot seized; the third one, the number of shot that hit the big 
circle; and the fourth one, the number of shot that were thrown 
in the pocket. As nearly all of the shot that were seized were 
thrown so that they hit the big circle, the second and third parts 
run along almost together. 

The subject's attention during the first two or three practices 
was almost entirely upon the disk. He was not able to take his 
eyes off the board long enough to look at the pocket and then 
return them in time to make a stroke at the next shot. He then 
tried to remember the general direction of the pocket. About 
the third practice, he felt that he was getting a better idea of 
this direction. He soon found that he had trouble handling the 
tongs. He would hit the shot but they would roll away from 
the end of the tongs. This trouble represents a period from the 
third up to about the fifteenth practice. The wide fluctuations 
on the sixteenth, seventeenth, eighteenth and nineteenth practices 
are the result of trouble with the motor. The belt slipped at 
first so that the disk rotated about one revolution per minute 
slower. After it was tightened the disk was unsteady in its mo- 
tion so that the subject was not able to get hold of the shot. 

It will be noted that very little progress had been made in the 
second and third parts during the time that the subject was 
having trouble with the tongs. The fourth part showed some 
slight improvement which was due to the subject's gaining a 
better idea of the general direction of the pocket. 

The first part shows that the subject had trouble hitting the 
shot up to the fifty-first practice. About that time he com- 
menced to watch the disk that carried the shot make one full 
revolution before he started to strike. He noted the exact po- 
sition of every shot and, as he said, had a mental picture of just 
how it looked. It may be seen that parts two and three shortly 
after this, rise to a higher level. They had remained almost on 
the same level from the nineteenth to the sixtieth practice with 



ACQUISITION OF SKILL 67 

the exception of the marked drop between the thirty-fifth and the 
forty-second practices. Here the subject developed a habit of 
bringing the shot back with the return stroke of the tongs. This 
bothered him so that he was not able to grasp the next shot. He 
discovered the trouble to be due to having changed very slightly 
the angle of the tongs when releasing the shot. Instead of having 
the end that contained the shot point toward the pocket, he had 
been holding them so that the end pointed down toward the table. 
When he opened the tongs under this condition the quick back 
motion did not give the shot time to drop but carried it back. 

During the time from the fifteenth to the fifty-seventh practice 
the fourth part shows practically no improvement. He had been 
trying to seize and throw all the shot without trying, directly, to 
improve the manner of locating the pocket. It may be noted that 
shortly after the first part had been perfected, the second and 
third also rose to a higher level. His concentrating his attention 
upon the position of the shot enabled him to seize them oftener. 

This may in part account for the rise in the fourth part from 
the fifty-ninth to the sixty-third practice. But the subject dur- 
ing this time discovered another change. He at first noted that 
standing with his feet in a certain position gave him a certain 
balance that he did not have otherwise. He later found that 
when he stood with his feet in this position and stretched out his 
arm straight towards the pocket, the end of the tongs rested 
about one and one half inches from the center of the pocket. 
This was the position in which he could do the best work and 
after he had discovered this way of locating it he always stretched 
out his arm and took the proper position before starting. 

There is not much improvement in any of the parts after this. 
The subject was very desirous of getting a perfect record even 
up to the end of the practice and thought he could do so if he 
had had a few more times to practice. He succeeded a few times 
in making as many as six rounds of the disk or seventy-two 
strokes without missing. This chance to see any variation in the 
progress gave an added incentive for greater effort. At the end 
of the practice, the subject was asked to write out the fact*" :s, as 
he remembered them, that helped him in the work. 



68 WILLIAM HOWARD BATSON 

He gave the following outline : 

"Some factors that were important in this experiment: 
I — ^Concentration of mind on the work before beginning. 

a. Must have a clear conception of the apparatus in mind. 

b. Must think of the actual work to be done. 

c. Must think of the distance, direction, and position of the pocket as 

related to the revolving disk. 
2 — Getting the proper position. 

a. Stand with the feet separted about two feet. 

b. Stretch the hand that holds the tongs toward the pocket until the 

tips of the tongs are about one and one-half inches from the center 
of the pocket. Then look down the arm to see that the same relative 
position is gained each time. After this, move the hand back and 
forth as if throwing the shot to insure absolute freedom of the arm. 
Just before beginning, fix the eyes upon the revolving disk, and at 
the same time look out of the corner of the eye at the pocket. After 
the body is in a proper position, let the disk make one complete 
revolution. During this time look steadily at the shot to see that 
they are in their proper position. Not only the motion of the disk 
and the position of the pockets must be related but the time rate 
of the arm movement must be clearly in mind. 

3 — In order to do the best work, must have a feeling that the arm is 
absolutely under control. 

4 — iMust have confidence; yet overconfidence sometimes produces a low 
score. 

5 — ^Must have a strong purpose in mind, in order to do best work." 

The increase in the subject's power to concentrate his atten- 
tion upon the work was very noticeable. After he had practiced 
several times, the work appeared to take hold of him. There 
was a set to his whole body and a certain rigidity that was en- 
tirely absent at first. This grew into a habit so that when the 
subject watched one of the other subjects perform he was ap- 
parently under this strain. A very high degree of accuracy with 
great speed was required but since each trial lasted but slightly 
over five seconds, the fatigue element did not enter. 



ACQUISITION OF SKILL 69 

TABLE XVII 

Subject M. 

Experiment — Throwing shot. 

The first column shows the date of practice. The second column shows the number 

of shot hit; the third, the number of shot seized; the fourth, the number of shot 

in the big circle; and the fifth, the number of shot in the pocket. This 

outline is true of each of the three divisions on the page. 

Jan. 20 56 40 27 12 Mch. 8 Apr. 24 

21 79 58 46 16 9 78 60 so 27 25 80 78 yy 74 

22 80 61 SI 21 10 80 67 s6 41 26 

23 80 S9 S2 26 II 80 72 68 57 27 80 78 yz 69 

24 79 55 49 19 12 80 6y 63 43 28 80 73 73 67 

25 13 79 ^ 60 28 29 ^ yy yy yo 

26 80 70 60 31 14 yg €y 59 38 30 80 78 78 69 

2y 80 59 53 21 15 May i 80 yz y2 s8 

28 74 55 SI 17 16 80 72 70 35 2 80 yy 75 66 

29 79 60 52 17 17 79 68 60 34 3 

30 80 60 57 21 18 80 68 66 45 4 80 76 76 70 

31 80 59 52 24 19.... 80 72 69 52 5 80 74 71 67 

Feb. 1 20. 77 6s 64 41 6 80 77 74 60 

2 80 59 S3 32 21 80 71 68 49 7 80 71 71 60 

3 77 SI 43 24 22 8 80 73 74 51 

4 79 61 SI 36 23 80 66 66 26 9 80 74 74 61 

5 79 61 50 29 24 80 71 69 Z2 10 

6 80 6s 59 47 25 80 y2 66 38 n 80 75 75 (>7 

7 80 74 68 49 26 80 66 63 44 12 80 78 75 69 

8 27 13 80 79 75 73 

9 79 58 48 18 28 80 74 69 49 14 80 73 73 67 

10 79 66 59 26 29 IS 80 74 74 67 

II 80 71 62, 47 30 80 6S 65 29 16 80 7S yz 68 

12 80 68 63 31 31 17 

13 75 6s 59 44 Apr. i 80 71 67 57 18 80 77 7^ 74 

14 79 75 68 56 2 80 73 71 so 19 80 yy 76 71 

IS 3 80 73 71 54 20 80 72 72 67 

16 79 74 70 28 4 80 72 66 56 21 80 80 78 73 

17 80 74 68 45 5 22 80 78 77 74 

18 78 71 67 43 6 80 73 68 53 23 80 77 77 72 

19 79 68 6s 42 7 80 75 73 68 24 

20 8 80 78 78 68 25 80 76 76 70 

21 9 80 74 74 70 26 80 78 77 67 

22 10 80 77 75 63 27 80 78 78 75 

23 80 74 65 54 II 80 78 74 64 28 80 80 78 72 

24 78 65 61 45 12 29 80 73 73 68 

25 80 69 61 42 13 80 76 72 59 30 80 77 76 70 

26 80 72 70 62 14 80 75 75 6s 31 

27 80 70 67 58 IS 80 76 75 65 June 1 80 76 75 67 

28 79 69 64 50 16 80 79 73 61 2 80 75 75 68 

Mch. 1 17 80 80 79 71 3 80 76 75 65 

2 78 67 60 3S 18 80 77 77 72 4 80 78 77 75 

3 80 71 62 54 19 5 80 78 77 73 

4 79 65 S3 47 20 80 75 75 67 

5 79 62 so 36 21 80 78 77 62 

6 80 63 40 32 22 79 75 75 71 

7 78 62 48 37 23 80 78 77 68 

Subject Fe. commenced work on Jan. 20 and continued until 

June 4, 1 91 4. The practice was daily except as noted in Table 



70 WILLIAM HOWARD BATS ON 

XVIII. The conditions under which he worked and the instruc- 
tions were the same as those for Subject M. The result of his 
work is shown in Table XVIII and the form of his improve- 
ment by Curve XXVII (Plate VI). 

This Subject did not analyse his manner of procedure as 
closely as did Subject M. He at first gave his attention to the 
seizing of the shot but after a few trials he grasped the situation 
as a whole. By examining the curves, it is seen that there is 
considerable difference between his work and that of Subject M. 
His first part was perfected somewhat more quickly. He failed 
to make a perfect score only four times after the thirty-second 
practice. Subject M. had trouble with this part of the work up 
to the fifty-first practice. 

The second and third parts rise rapidly at first and then gradu- 
ally until about the fiftieth practice. After that they remain al- 
most on a level fluctuating between seventy-six and eighty. The 
fourth part makes practically no progress until the sixth practice ; 
after that it rises rapidly until the ninth practice. The large 
fluctuations between the fourteenth and seventeenth practices 
were due to the belt slipping on the motor. If this trouble had 
not occurred, it is likely the rise would have followed a more 
gradual course up to the thirty-sixth or thirty-ninth practice. 
After that there is a period of practically no progress up to the 
sixty-first practice, or during twenty-three or four days. At that 
point, he found that he could give a longer swing to his arm 
and thus hit the pocket more often. This brought the fourth 
part to the final level which lasted to the end of the practice. 
Except this last case, the subject did not discover any factor 
that had helped him in the improvement. 



ACQUISITION OF SKILL yi 

TABLE XVIII 

Subject Fe. 

Experiment — Throwing shot. 

The first column shows the date of practice. The second column shows the number 
of shot hit; the third, the number of shot seized; the fourth, the number of shot 
in the big circle; and the fifth, the number of shot in the pocket. This 
outline is true of each of the three divisions on the page. 

Jan. 20 y6 58 30 oMch. 7 80 72 67 spApr. 22 80 79 yy' 58 

21 80 69 47 I 8 23 80 77 73 70 

22 79 70 41 2 9 24 80 78 78 74 

2Z 80 67 40 o 10 80 75 75 61 25 80 80 80 69 

24 80 65 58 3 II 80 75 73 64 26 

25 12 80 75 71 56 27 

26 13 80 77 74 62 28 80 80 80 70 

2y 78 61 62 12 14 80 yy 74 61 29 80 76 76 y2 

28 80 61 57 16 15 30 Bo yy yy y^, 

29 79 68 60 28 16 'May i 80 80 78 yj, 

30 79 59 53 31 17 80 77 75 64 2 

31 78 68 64 26 18 80 78 77 65 3 

Feb. 1 19 79 69 69 58 4 

2 20 80 79 76 68 5 80 79 78 57 

3 78 64 58 20 21 80 79 76 68 6 80 yy y6 66 

4 79 70 62 29 22. 7 80 77 76 67 

5 79 73 70 25 23 8 80 78 78 67 

6 75 70 56 33 24 80 78 76 62 9 80 79 79 y2 

7 77 75 64 53 25 79 78 yy 6y 10 

8 26 80 80 79 66 II 

9 2y 79 72 72 65 12 80 80 79 74 

10 79 73 68 35 28 80 79 76 69 13 80 yy ys 67 

II 80 74 64 56 29 14 80 80 80 74 

12 80 74 71 45 30 15 80 80 80 72 

13 80 y3 64 45 31 80 75 74 61 16 80 80 80 6s 

14 79 70 62 46Apr. 1 80 yy yy 68 17 

15 2 18 

16 3 19 80 78 78 70 

17 80 71 66 46 4 20 80 79 79 69 

18 79 71 69 39 5 21 80 80 80 77 

19 80 75 71 43 6 22 80 yy yy 69 

20 78 70 68 36 7 80 yy y6 70 23 80 79 79 69 

21 80 71 67 36 8 24 

22 9 80 77 76 83 25 

23 10 80 79 79 67 26 80 79 77 70 

24 80 y3 69 35 II 80 yy yy 62 27 80 80 79 72 

25 79 77 74 so 12 28 80 80 80 75 

26 80 72 71 55 13 29 80 77 76 72 

2y 80 yy 75 50 14 80 y6 76 61 30 80 78 75 64 

28 80 yy y6 54 i5 80 79 yy 52 31 

Mch. 1 16 79 78 77 52 June i 

2 17. 80 78 77 60 2 80 77 76 73 

3 79 77 74 5i 18 80 79 79 69 3 80 79 78 76 

4 19 4 80 76 76 71 

5 80 74 73 56 20 

6 80 yy 72 54 21 80 yy 75 65 

Subject S. commenced work on Apr. 2, and continued until 

May 29, 191 4. She worked under the same conditions as the 

other two subjects and was given the same instructions. The 



72 WILLIAM HOWARD BATSON 

results of her work are given in Table XIX. Curve XXVIII 
(Plate VII) shows the nature of her improvement. During the 
first two practices she said that the motion of the disk made her 
dizzy. After that she experienced no more trouble in this respect. 
She mastered the manipulation of the tongs more quickly than 
did the other two subjects. The quickness and accuracy of the 
hand movement enabled her, after about the seventh practice, to 
devote all her attention to the throwing of the shot. This made 
her problem nearly the same as when only one factor was to be 
observed. 

An examination of the curve that represents her progress 
shows that after the seventh practice the first three parts show 
little improvement. With a few exceptions, the second and 
third parts fluctuate between seventy-six and eighty. The fourth 
shows an almost constant rise with the usual daily fluctuations. 

TABLE XIX 

Subject S. 

Experiment — Throwing shot. 

The first column shows the date of practice. The second column shows the number 
of shot hit; the third, the number of shot seized; the fourth, the number of shot 
in the big circle; and the fifth, the number of shot in the pocket. This 
outline is true of each of the three divisions on the page. 

Apr. 2 71 55 54 i2Apr. 23 80 77 77 35May 13 80 78 78 51 

3 73 65 59 12 24 80 75 75 45 14 80 75 74 62 

4 79 69 64 23 25 80 78 78 47 15 80 79 79 59 

5 26 16 80 77 76 42 

6 73 69 57 17 27 80 75 74 46 i? 

7 79 73 61 22 28 80 79 77 60 18 80 77 77 52 

8 78 72 68 25 29 80 79 79 65 19 80 79 78 59 

9 80 75 72 23 30 80 79 76 55 20 80 77 76 67 

10 80 76 76 3.5May i 80 77 64 48 21 80 78 78 59 

II 80 80 77 28 2 80 77 77 42 22 80 76 76 54 

12 3 23 80 79 79 63 

13 80 75 71 44 4 80 76 73 44 24 

14 80 75 75 39 5 80 80 78 51 25 80 79 79 63 

15 80 73 72 37 6 80 77 75 57 26 80 78 78 60 

16 80 80 78 37 7 79 77 77 56 27 80 79 79 63 

17 80 80 77 34 8 80 77 77 48 28 80 77 77 69 

18 80 74 72, 32 9 80 78 78 61 29 80 78 78 72 

19 10 30 80 78 77 67 

20 79 71 70 27 II 80 78 76 60 31 

21 80 78 77 40 12 June 1 80 78 78 72 

22 80 77 77 37 13 



ACQUISITION OF SKILL 73 

Subject Cd. was selected primarily because she had had a 
large amount of practice on the piano. She commenced work 
on April 2, and continued until May 29, 1914. The conditions 
under which she worked and the instructions given were the same 
as those for the other subjects. The result of her practice is 
shown in Table XX and the form of improvement is shown in 
Curve XXIX (Plate VIII). She did the work with a sort of 
passive indifference. There was no sign of the effort which was 
so characteristic of the other subjects. She was able to improve 
very rapidly. In six days the first three parts had reached a level 
that was not improved afterwards. In twelve practices the 
fourth part had reached a level that on an average was not sur- 
passed during the rest of the practice. From the twelfth to the 
forty-third practice there was little improvement. This seems to 
indicate that the work was partly done when she started. The 
point that was hardest for the other subjects, that of the position 
of the pocket, caused her no particular trouble. After just a 
few practices she would move her nand exactly to the same point 
and in the same way. 

TABLE XX 

Suibject Cd. 

Experiment — .Throwing shot. 

The first column shows the date of practice. The second column shows the number 
of shot hit; the third, the number of shot seized; the fourth, the number of shot 
in the big circle; and the fifth, the number of shot in the pocket. This 
outline is true of each of the three divisions on the page. 

Apr. 2 64 61 30 ooApr. 22 79 y:^ 71 44'May 11 

3 72 64 60 IS 2Z 80 74 72, 55 12 79 79 76 59 

4 78 70 69 21 24 79 70 67 45 13 80 73 7z 52 

5 25 80 76 72 65 14 80 74 75 61 

6 74 72 68 13 26 15 80 77 77 67 

7 77 72 71 30 27 80 72 70 55 16 80 74 74 62 

8 80 75 72 21 28 80 74 73 61 17 

9 79 71 70 26 29 79 73 71 54 18 

10 80 78 76 38 30 79 68 67 42 19 80 74 73 54 

II 80 79 79 35May i 80 76 75 58 20 80 75 74 46 

12 2 76 68 67 53 21 79 71 71 54 

13 79 71 71 30 3 22 

14 78 75 74 44 4 80 70 69 55 23 80 76 76 61 

15 80 78 74 57 5 79 73 69 51 24 80 73 72 64 

16 79 71 69 48 6 80 76 75 45 25 

17 80 79 76 62 7 78 69 69 47 26 

18 80 76 72 63 8 80 73 73 53 27 

19 9 80 72 71 55 28 79 71 71 56 

20 10 29 80 77 74 64 



21. 



74 WILLIAM HOWARD BATSON 

By- comparing these four curves, it may be seen to what extent 
each of the four factors influenced the work and what the effect 
is on the form of the curves. It will be seen that in all the curves 
except XXVIII the problem of hitting the shot was not mastered 
until several weeks practice. This period was extended longest 
in the case of Curve XXVI. In Curve XXIX, this element caused 
trouble until the end of the practice. 

The second and third parts of Curve XXVI show three rises 
and three plateau periods. The first rise from the first to the 
third practice represents the period when the subject was getting 
acquainted with the rate of rotation of the disk. From the third 
to the fifteenth practice, his attention was on the general direc- 
tion of the pocket and on the tongs. At the sixteenth practice 
there was a marked improvement in his ability to handle the 
tongs. From the sixteenth to the fiftieth practice the attention 
was centered on seizing and throwing the shot while the hitting 
of the pocket was ignored. At the fifty-first practice, the subject 
commenced to watch one full rotation of the disk before starting 
to strike and he continued to attend to this phase of the work 
until the fifty-seventh practice. Here he improves his seizing on 
the basis of better striking and also notices a better way of 
standing. 

Curve XXVII shows no such steps in the second and third 
parts. There is a general rise up to about the fiftieth practice 
and after that little improvement. The subject's manner of at- 
tending gave him no factor for separate consideration. The 
second and third parts of Curve XXVIII show about the same 
form as the same parts of Curve XXVII. The first factor hav- 
ing been mastered after about six practices there was no element 
to cause trouble and no particular improvement in the plan of 
the work. In Curve XXIX the second and third parts rose 
rapidly for four or five practices, but did not succeed in reaching 
so high a level for this part of the work as that reached by the 
other subjects. 

Curve XXVI shows in the fourth part a very pronounced 
plateau type of curve. At first, there is a slight rise partly due 
to the subject's getting acquainted with the apparatus and partly 



ACQUISITION OF SKILL 75 

the result of his improving the method then being used. After 
about sixteen practices, a level was reached in this part of the 
curve that remains practically constant until the fifty-eighth prac- 
tice. What was going on at this time may be partly accounted 
for by noticing the other parts. The rise to the next level in- 
volved two factors at least. One was this mastering the first 
element and the second followed as a consequence from this. 
The subject being somewhat free discovered the proper way to 
get the most suitable standing position. He had noted a feeling 
of ease when in the proper position even before he had analysed 
a method to make sure of it every trial. 

The fourth part of Curve XXVII shows no improvement for 
four practices. During this time, the subject had given all his 
attention to the other factors. Then by attending the whole 
problem he reached a level at about the forty-first practice which 
seemed to have been the limit for the method he was using. 
After he had discovered a new method, that of extending his 
arm farther, he brought this part of the curve to the next level. 
The fourth part of Curve XXVIII shows a constant rise for the 
reason that the subject was attending to this part from the 
first. No especial changes in method were noted. The fourth 
part of Curve XXIX shows a rapid rise for a few practices which 
seems to have been the result of adapting an ability already ex- 
isting to this new situation. After this process had become per- 
fect no further advance was made. No new method was devised 
and no special effort was put forth. There was a drop from the 
twenty-first to the thirty-second practice which appeared to be 
the result of indifference. 

GENERAL DISCUSSION 
The first aim of this study was to get further information in 
regard to the long period fluctuations or plateaus in the curve of 
learning. It is seen from these experiments that only in the last 
division of the work are there plateaus of long length. Neither 
in the ball tossing experiments nor in the work done by Swift, 
although the work extended over a considerable period of time 
in some cases, does there appear a long arrest between two rapid 



•]6 WILLIAM HOWARD BATSON 

progress periods. The middle division of this work where only 
one element was involved did not in any case extend over a 
period of time of sufficient length to show a long plateau. In 
the last division of the work, however, in one case in particular 
the plateaus were very pronounced if the part representing the 
shot thrown in the pocket is considered. 

No one, so far as the writer is aware, has contended that the 
long period plateaus are a necessary part of all learning curves 
regardless of the type of learning. Bryan and Harter, however, 
in their work were convinced that these long periods of slow 
progress were necessary in the curves for receiving the tele- 
graphic language. Book found the long period fluctuation in 
two of the curves he obtained for learning typewriting but he 
did not think they were a necessary part of the development. 
The last division of this work shows that there may be or may 
not be plateaus of long length in the same type of work. 

One way of deciding the question of the necessity of plateaus 
for a particular type of learning would be to try a large number 
of individuals and see if they uniformly had plateaus in their 
improvement. Another way and a more satisfactory plan would 
be to attempt to analyse out the factors and see just what is in- 
volved in the formation of the arrest period. It has been seen 
(see Introduction to this study) that Bryan and Harter attributed 
the plateaus to the time it takes to form different-order habits : 
Swift, although he found only short plateaus, believes for the 
most part that they can be explained on the basis of the associa- 
tions being made automatic; and Book thought they were the 
result of lapse of attention or misdirected attention. In none of 
these publications was an attempt made to so arrange the work 
that an opportunity would be given to see just how the separate 
factors acted during a plateau period and what effect the dif- 
erent reactions to them by different subjects had upon the work 
as a whole. 

The last division of the work reported in this study was 
planned with the intention of having a number of elements in- 
volved in such a way that the subject could attend to all of them 
at once or attend to one or more of them separately from the 



ACQUISITION OF SKILL 77 

rest. It may be objected that the factors that were measured in 
this work must follow one another in a certain order and that 
the subject could not modify this or in other words change the 
order of the factors. This is true,' — the subject could not throw 
or hit the pocket until he had struck or seized the shot — but this 
did not prevent him from giving practically all his attention to 
the first factor or distributing it over the work as a whole. What 
occurred in the subjects tested for this work may be seen by 
examining the different divisions of the curves obtained for the 
four subjects used in this experiment. 

If the last or fourth part (the part obtained by using the shot 
that hit the pocket as a unit of measure) of the curves for each 
of these subjects be observed, it will be seen that one of the sub- 
jects (Subject M.) had two rises and two marked plateaus. 
Subject Fe. showed a short arrest period at first, a rapid rise 
and then another period of arrest. Subject S. showed no sign 
of an arrest period in this part of her work but an almost con- 
stant rise from one end of the curve to the other. Subject Cd. 
at first showed a rapid rise and then a long period of delay which 
was not broken at the end of the practice. 

If the hitting of the pocket had been the only goal and the unit 
of measure had considered nothing else, the explanation of the 
curve would have had to depend upon introspections. Here, 
however, the other parts of the curve give an objective basis for 
explanation. Subject M. who had two pronounced plateaus at- 
tacked the work in parts ; he attended to the first or basal factor 
until it was under a high degree of control. After that he took 
up the other factors. It is true the improvement was due, in 
part, to improvement in method but this depended upon the fact 
that his attention was free to attack the other part of the prob- 
lem. In this case the subject followed a plan parallel to what 
Bryan and Harter explained when they spoke of the lower order 
habits being completed or automatized first. There was no evi- 
dence in this subject of a lapse and renewal of attention as Book 
pointed out in his work on typewriting. It may be that the work 
was such that the subject could see that he was making progress 
all the time ; that is, he could see that he was hitting the shot or 



78 V/ILLIAM HOWARD BATSON 

seizing them better and this kept up his interest. However, the 
fact stands that it was not lapse of attention that caused the 
long arrest in the fourth part of the curve. 

Subject Fe. had a short period of arrest in the fourth part of 
his curve, while there was a relatively large improvement in the 
other parts. This indicated that he was attending to those first 
factors. Later all the parts of the curve make gains together. 
He was able to attend during this time to the process as a whole. 
When he reached a level near the limit of his ability to improve, 
all the divisions of the curve sloped off more nearly parallel to 
the X-axis. 

Subject S. had no plateau in the fourth division of her work, 
because, as can be seen from the other three parts of her curve 
the first three factors presented her no trouble. As has been 
explained, the quickness of her hand movement and the accuracy 
with which she used the tongs enabled her to master these factors 
in a short time. In her work, it was simply a case of giving her 
attention to a single factor and the curve of the type of the 
simple association curve (see discussion on the form of the 
curves) was the result. 

Subject Cd. had much the same form of curve in the fourth 
part but the rise was more rapid. The reason for that has been 
explained already. The practice on the piano was a training that 
only needed special adaptation. This took place rapidly. After 
that she improved the work in a short time to a point near the 
limit of her ability. 

From this study and from the other experiments done in this 
field, the writer feels justified in drawing the following conclu- 
sions in regard to the plateau. There is no evidence to show that 
they ever occur in learning processes where there is only a single 
association involved. They may or may not occur in a complex 
learning process. If the factors involved are of such a nature 
that they must be improved together or if the subject is able to 
attend them as a whole, there will be no plateau. If, however, 
the nature of the work is such that the factors must be attended 
in succession or the subject gives his attention to the separate 
factors, as such, there will be plateaus. 



ACQUISITION OF SKILL 79 

Ball-tossing may be taken as an illustration of where the 
factors involved must be improved together. At least three of 
these factors have been mentioned and studied to some extent in 
this work. If these factors are taken, it is seen that it is prac- 
tically impossible for the subject to separate them. One of them 
counts for nothing unless the others go along with it. It might 
be conceived that the subject could practice throwing the ball a 
certain height or in a certain direction, yet in this case, he would 
either have to watch it or use some other means to get a selective 
factor, that is, to show when an improvement is made and this 
would give him a criterion for the time element. Again if he 
improves his ability to throw in a certain direction and does not 
improve his ability to shift his hand to the position where the 
ball will fall, there will be no improvement in the unit of measure. 

In the work on throwing the shot, the separate factors could 
be improved in succession. The subject could practice with his 
attention fixed on the seizing of the shot until he had acquired 
the ability to hit and seize practically every one in order, or he 
could distribute his attention on the separate factors about equal- 
ly. The aim was to have the subjects learn each factor in order 
but some of the subjects were more completely able to do this 
than others. In such cases as this last division of work where 
the shot throwing is the problem, the attention will be given to 
a part or the whole of the work according to all the conditions 
that govern the attention of the individual at the particular time 
of the practice. 

The Daily Fluctuations 
The daily fluctuations appeared in all the work that was done. 
In fact there seem to be no cases of learning where they do not 
appear. They indicate very clearly the variation in the physical 
and mental condition of the subject from day to day. At times 
the subjects were able to tell in advance that they would make a 
good score but in this work, just as Swift found, their thinking 
that they would make a good score was no proof that they 
would. It was noted that Subject F. in his tossing the pieces of 
hard rubber was set back by his confidence that he would make 
a high score after the first relatively high score. 



8o WILLIAM HOWARD BATSON 

Whether these fluctuations were greater at the beginning or 
at the end of the practice depended upon the nature of the work 
and the unit of measure. If there was a definite set Hmit for 
the unit of measure as in the case of the direction, force, and 
time curves, or in the shot throwing curves, the later variations 
were Hkely to be less. But on the contrary if the unit of measure 
had no limit other than fatigue or some physical or mental factor 
as in the case of the ball-tossing, the later fluctuations were rela- 
tively large. 

This work differs from a large part of the experimental work 
that has been done in this field in that the material from day to 
day was kept exactly the same. In work like typewriting, short- 
hand, and telegraphy where different material is used on suc- 
ceeding days, the fluctuation may be partly at least accounted 
for by the fact that the subject matter was more difficult on some 
days than on others. 

The fluctuations are useful for indicating the relative amount 
of ability shown daily by subjects doing the same kind of work 
but it must be remembered that the nature of the unit of measure 
will largely determine the apparent amount of fluctuation each 
day. It may also be noted that because the fluctuations are 
larger toward the end of the curve, one should not conclude that 
the daily ability varies more at that time of the practice. 

The time and direction curves may be taken to illustrate the 
first point. Because the average deviation of the time curves 
was less than that of the direction curves, it does not follow that 
the subjects varied less daily from a certain line of improvement 
in judging time than they did in judging direction. If more 
pockets had been made on the disk, the variation for the time 
test would have been greater though the actual daily ability 
would have been the same. 

Again if the ball tossing curves, where the number of catches 
form the unit of measure, are noticed, it will be seen that the 
latter part of the curves shows wide daily fluctuations. If it 
were true that catching ten balls meant the same whether they 
are the first ten or the ten between ninety and a hundred then 
these fluctuations near the end of the curve would mean a greater 



ACQUISITION OF SKILL 8i 

daily variation in ability, but no one is likely to contend that this 
is true. 

That the fluctuations may be seen to be due to the nature of 
the unit of measure, attention need only be called to the forms 
of Curves Ila and IVa, The latter part of these curves shows 
little variation and gives a directly opposite result from what the 
first method of plotting the ball tossing curves seems to indicate. 

The General Form of the Curves 

For the purposes of discussion, the curves of learning may con- 
veniently be divided into four classes. When the number of 
catches in a given number of trials (Curves I to V), the recipro- 
cals of the number of errors per given group (Curves IX and X) 
as five hundred or one thousand, or the average number of catches 
in thousand groups (Curves XI to XV) are used as the basis 
for the unit of measure the curves all show the same general 
form. They are all concave to the y-axis. Some of them do not 
show this peculiarity to so great an extent as others but this can 
be explained on the ground that the subject had had previous 
practice or similar practice which modified the form of the early 
part of the curve. 

Another class is where the slope is relatively constant up or 
down, accordingly as the unit of measure is such that it increases 
or decreases, until a point is reached near the limit of the sub- 
ject's skill. This class is illustrated by the experiments on di- 
rection, force and time. 

A third class is where the curve rises or falls rapidly at first 
and then gradually approaches parallelism with the x-axis. This 
class is illustrated by the second and third divisions of some of 
the shot throwing curves and those for telegraphic sending in 
the study of Bryan and Harter; also by the ball-tossing experi- 
ments when the unit of measure is the number of errors made 
in catching a definite number, as five hundred or a thousand, or 
the percent the number of catches is of the number of tosses. 

The fourth class is the long level plateau class where there is 
a relatively rapid rise and then a period of delay and then an- 
other period of rapid rise. This is illustrated by the fourth part 



82 WILLIAM HOWARD BATSON 

of the curve of Subject M. obtained for shot tossing, and also by 
some of the typewriting curves of Book and the telegraphic re- 
ceiving curves by Bryan and Harter. 

The curves for ball tossing when the unit of measure is the 
number of catches made in a certain number of trials, show a 
long period when comparatively little progress is made and then 
a sudden rise at the end. This is true regardless of whether the 
subject attempts to use a particular method, or to develop some 
special part of the work. It is true also regardless of the distri- 
bution of practice. When the subject had a practice period of 
approximately five hundred catches instead of ten trials, the 
curve obtained when ten trials was made the basis of the score, 
was the same in form (Curve VIII). 

There are a number of factors that must be considered in try- 
ing to interpret the significance of this type of curve. The long 
period of apparent slow progress at the beginning of the ball 
tossing curves where a number of trials is made the unit for the 
divisions on the x-axis and the sum of the catches is the basis 
for the divisions on the y-axis may be explained by the fact that 
the long period represents relatively little practice. When the 
subject is able to make less than one hundred catches during the 
ten trials he gets much less practice than when he can make a 
thousand or more catches in the same number of trials. This 
holds true for Curve VIII, when the practice period was five 
hundred but the divisions on the x-axis were based on groups of 
ten trials as well as for the first five ball tossing curves. 

The rapid rise at the end of all the curves of this type is due to 
the peculiar nature of the unit of measure; that is, in the ball 
tossing curves where the number of trials is used as the basis 
for divisions on the x-axis (Curves I to V and also VIII) ; the 
curves where the reciprocals of the number of errors per given 
group as five hundred or one thousand (Curves IX and X) are 
used; and the curves where the averages per thousand (Curves 
XI to XV) are made the basis for the divisions on the y-axis. 

In the case of Curves I to V and VIII, ten trial groups are 
made the basis for divisions on the x-axis but a trial here means 
the number of catches between two errors or misses. It follows 



ACQUISITION OF SKILL 83 

that the significance of a trial in the earHer and later part of the 
work in any experiment varies greatly. The implication is that 
ten catches represent the same amount of skill whether they are 
made on the first day's practice or on the last day's practice or 
whether it is the first ten caught or the ten between ninety and 
one hundred, and that to catch one hundred balls in one trial 
represents a degree of skill ten times as great as to catch ten 
balls in one trial. 

In all the other experiments of this work, the unit of measure 
would be comparable to a single toss, that is the toss would con- 
stitute a trial. The degree of skill would be represented by the 
proportion of tosses that are successful. If the subject catches 
ten balls the first time before he misses, he has ten successes out 
of eleven trials or ninety-one percent would represent his degree 
of skill. When he catches one hundred balls without missing, he 
has ninety-nine percent for his degree of success. Instead of 
his success or skill being ten times as great in the second case as 
in the first as it would be by the first method, it is really only 
eight per cent greater. 

In the curves where the reciprocals of the number of errors is 
made the basis for the divisions on the y-axis the result is the 
same as where the ten trial basis is used. The assumption is that 
to catch one hundred balls in one trial represents a degree of skill 
ten times as great as to catch ten balls in one trial. The effect 
can be seen readily by noting that the vertical distances (distances 
above the x-axis) vary as a constant divided by a decreasing 
variable. 

When the data used in plotting these first curves, that is the 
first five for ball tossing are used so as to make the actual amount 
of practice the basis upon which to count gain in skill a very 
different form of curve is obtained (see curve Ila and IVa). 

In these cases the basis was one thousand catches which was 
a definite amount of practice and the success was measured by 
counting what percent this was of the total number of tosses 
necessary to make the thousand catches. The implication is that 
a miss is no practice, at least it gives no increase in skill. This 
method gives practically the same form of curves as taking the 



84 ■ WILLIAM HOWARD BAT SON 

number of catches made in each one thousand tosses as the basis 
for divisions on the y-axis. Instead of measuring the absohite 
gain this method measures the relative gain. With this method 
of measuring gain, there is no rapid rise at the end of the curves. 

Thorndike using Swift's data points out that when the average 
number of tosses is used as the basis for the divisions on the 
y-axis and the thousand groups are the basis for the divisions on 
the X-axis, a curve of the form of type three is the result.^^ 
The data obtained in this work do not give that form of curve 
when treated in that way. 

The second class of curves is where the slope remains up or 
down depending on whether the unit of measure is such that 
the values representing the divisicns on the y-axis increase or 
decrease with the increase of skill until a point of development 
is reached near the limit of its possibilities. This may be de- 
termined by the particular function having been perfected as in 
the case of direction if the subject could have hit the mark every 
time or by his approaching a place where he could no longer get 
a selective factor, that is he passes into a realm beyond the 
threshold of sensory discrimination in that particular field. For 
instance, if the experiment on force is taken as an example it may 
be conceived that the subject will be able to hit within a certain 
minimum distance of the mark every throw but after he reaches 
a plane where the difference required to put the ball within that 
space and beyond it falls below a certain fraction of the weight 
of the ball that he is throwing, he would be able no longer to 
control the ball so as to reduce the score. At this point the curve 
would slope off so as to become practically parallel with the 
x-axis. Sometimes in the case of a single factor acting, the ap- 
paratus may at first cause some confusion so that the first few 
scores may be abnormally high. This makes it appear that the 
curve rises or falls rapidly at first. The curves obtained for the 
judgment of time are examples of this. 

All the simple association experiments in this work as well as 
those in other experiments that have been examined show a con- 
stant and gradual improvement with the daily fluctuations bal- 

2^ Thorndike, E. L. "Educational Psychology," Vol. II, p. 122. 



ACQUISITION OF SKILL 85 

ancing each other, as a rule, in such a way as to approach a 
straight line until near the limit of the development. 

The third type may be the result of a number of elements 
gradually becoming perfected together and as the elements ap- 
proach their limit the improvement grows less. Where the work 
is complex, and the unit of measure is such that it shows the full 
value of the improvement as fast as it is made, and the subject 
attends the process as a whole, the curve rises or falls rapidly 
at first and as the chance for improvement in the separate ele- 
ments becomes less the rise becomes less rapid. The curves for 
the sending of the telegraphic language illustrate this form as 
do also some of the curves obtained by Book in the typewriting 
experiments, and Curves Ila. and IVa. for ball tossing. 

The fourth class of curves is that of the long plateau form 
which has already been discussed under the head of long time 
fluctuations. In addition to what has already been said, it is 
interesting to note that Starch's work on tracing a six-pointed 
star {op. cit., p. 12) shows the effect of two elements working. 
He plotted a curve for speed and one for error. The error curve 
was of the third type and the time curve was in a measure like 
the fourth type. He does not so state but it is probable that the 
subject was giving his attention largely to the error side of the 
work while the plateau period lasted in the time or speed curve. 

The writer believes there is no typical curve for all types of 
learning. Where the work is so simple that the attention cannot 
be distributed as in the case of rolling a steel ball at a mark or 
the work is of such a nature that the attention must be given in 
a certain way, the curves are likely to be of similar form for 
different subjects. Where the work is complex and the attention 
can be distributed on different parts of the process, then the 
curve for different individuals will vary, though the work is the 
same. 

The Influence of Objective and Subjective Factors 

This subject has been discussed in detail by Swift and Book. 
Nothing more was noted in this work than that which empha- 
sizes what they have already said. The objective factors such as 



86 WILLIAM HOWARD BATSON 

light, temperature, nature of the work, and apparatus, were all 
very important and any change showed its effect especially in the 
early part of the practice. The same was true with the subjective 
factors. However these were not always so easily analysed out. 
All of these factors showed themselves more influential in the 
early part of the work when the attention was actively involved 
than later when the process was more automatic. The experience 
of expert telegraphers, pianists, and others where there is a large 
element of motor control involved, demonstrate this beyond 
doubt. This does not assert, however, that where speed is in- 
volved distraction of attention does not affect it. 

The Warming up Process 

A part of this work showed a warming up and a part did not. 
The work in ball-tossing shows clearly that after the first trial 
there were better results. Book also found this warming up ten- 
dency to a very marked degree in his work. In the experiments 
on the judgment of direction there was little evidence of warm- 
ing up. As the work was such that fatigue would not enter to 
any great extent, a division of the practice periods into two equal 
parts ought to show better results for the last half if there was 
any noticeable warming up. These figures do not show enough 
advantage to the last half of the work to be of any weight. Wells 
found in another experiment where a single association had to 
be formed that there was evidence of warming up to a consider- 
able extent. 

In a complex work, the warming up may take the form of 
renewed associations but in a simple work this is not necessary. 
It would seem that the difference between the work that Wells 
had his subject do, that of tapping at maximum speed on a 
telegraph key, and the work in learning direction consisted in 
this, that in the first case special preparation was necessary while 
in the other the ordinary movements of the day would be all 
that is necessary to keep the arm in proper condition. 

The Effect of Short and Long Rest Periods 
An examination of the ball-tossing experiments shows that 
there is no regularity in what happens after a short rest period 



ACQUISITION OF SKILL 87 

of a day or two. Sometimes the score is higher and sometimes 
lower. This was also true to a large extent in the shot throwing 
experiments. In the other experiments no opportunity was given 
to test the effect of short rest periods as the work was con- 
tinuous from the beginning to the end. 

The shot throwing experiments gave an opportunity to test 
the effect of a short rest period as the work was discontinued on 
Sunday each week. In the case of Subject Fe. both Sunday and 
Monday were missed each week. The work of Subjects M. and 
Fe. extended over nineteen Sundays. Subject M. threw more 
shot in the pocket on Saturday than on Monday eleven times out 
of the nineteen. Subject Fe., who had missed two days' practice 
threw more shot in the pocket on Saturday than on Tuesday nine 
times out of nineteen. Subject S. threw more shot in the pocket 
on Saturday than on Monday three times out of eight and Sub- 
ject Cd., six times out of eight. So far as this part of the com- 
parison goes it is seen that two of the subjects did better after 
the rest period and two did better before it. 

If, instead of counting only the number of shot put in the 
pocket, the whole work is considered, that is groups of figures 
in the four columns of the tables for the work immediately be- 
fore and after the rest periods, it is seen that for Subject M. 
thirty-one scores were better on Saturday than on Monday, 
twenty-four were better on Monday than on Saturday and the 
others are equal. Subject Fe. has twenty-eight better on Satur- 
day and twenty-two better on Tuesday. Subject S. has twelve 
better on Saturday and eleven better on Monday. Subject Cd. 
has twenty-one better on Saturday and eight better on Monday. 
The advantage seems to be slightly in favor of the practice pre- 
ceding the rest period. 

For the long rest period, the results show that where there was 
not a positive gain, a condition existed that made a rapid gain 
possible when practice was resumed anew. After a rest of more 
than six months, subject D. was able to make nearly as high a 
score the second practice period as he had made the last day in 
the regular period. Almost a year after this, he was able to 
make a score nearly twice as high as any he had ever made 



88 WILLIAM HOWARD BATSON 

before. This was in the first test made. Here was a positive 
gain with less than a half hour's practice having been taken dur- 
ing the intervening period. 

Subject B., after more than a year's rest, made a score on the 
first day that the practice was resumed with his right hand almost 
as high as he had ever made before. Two days later he was able 
to make a higher score than he had ever made before. The left 
hand had apparently not retained the same amount of skill as the 
right hand. However, the second retention test showed a marked 
improvement over the first. The score was as high as any he 
had ever made in the regular practice except the last three or four 
where the usual final spurt had occurred. 

Subject .W., after a rest period of nearly five months, made a 
score during his second practice higher than he had ever made 
during his regular practice. A little more than a year after this 
retention test, he made a score higher than any he had ever made 
in the regular practice and almost equal to the last score that he 
made in his first retention test. 

Subject F. was the only subject that did not show results in the 
retention test practically equal to or superior to the best scores in 
the regular practice. The reasons for this have been explained 
in the discussion of his work. 

Although the work was not carried very far, one interesting 
point to note is the rapidity with which the improvement takes 
place in the repeated retention tests. Subject D. in his second 
retention test which was taken two days after his first shows an 
improvement of nearly twenty-five per cent over the first one. 
Subject B., made a gain of almost thirty per cent in the second 
test over the first with his right hand. With his left hand there 
was a gain of forty-three per cent in the second test over the first. 
Subject W., in his second test, showed a gain of nearly ninety 
per cent over the first. Subject F. was the only subject that did 
not show a gain in the second retention test over the first. In 
his case there was a loss of about twenty per cent. 

It is interesting to note that this rapid regaining of an acquired 
ability is closely parallel to the rapid improvement in an instinctive 
response that has been delayed for a short time. Shepard and 



ACQUISITION OF SKILL 89 

Breed found in their study of chicks^ ^ that if the pecking re- 
sponse of the chicks is delayed for a few days the accuracy of 
the pecking increased much more rapidly than it did when the 
instinct took its normal course; in other words the chicks that 
had been delayed soon gained an ability equal to those that had 
normally developed. 

The only place in this study that a test was made for the effect 
of a long rest period, except the ball tossing experiments, was 
for direction with Subject W. His first test showed that he had 
apparently lost much of his former skill. The reason for that 
has been already given in the discussion of that experiment. His 
second test taken immediately afterwards showed that he had 
regained practically all the skill he had acquired by his previous 
training. 

The data obtained in these tests only confirmed what has been 
pointed out by Swift, Book, Wells, and others. 

Summary 

I. — The plateaus of learning depend upon the factors involved 
in the process to be learned and upon the distribution of atten- 
tion. They are not found in simple types of learning and may or 
may not be found in complex types. 

2. — The daily fluctuations are common to all types of learning 
and depend upon the objective and subjective factors involved. 
They may be deceptive because of the influence of the nature of 
the unit of measure upon them but they are useful for the purpose 
of comparing the daily variability of two or more subjects that are 
at the same point of development in doing the same type of work. 

3. — 'Both the factors involved and the attention of the subject 
influence the general form of the curves of learning. Where the 
work is simple, that is requires a simple sensori-motor associa- 
tion, there will be a typical curve common to different subjects. 
This is also true where the work is more complex and the factors 
must, from the nature of the work, be attended in a certain order. 

** Shepard, John F. and Breed, F. S., "Maturation and Use in the Develop- 
ment of an Instinct." Jour, of Animal Behavior. July-August, 1913, vol. 3, 
no. 4, pp. 274-285. 



90 WILLIAM HOWARD BATS ON 

4. — Objective and subjective factors have a very great influ- 
ence on the learning, especially in the early part of the work. 

5. — The warming up process is the necessary accompaniment 
of all work where the ordinary daily activity does not provide the 
special preparation required for performing the work effectively. 

6. — The results do not show that a short rest period has any 
marked effect on the work one way or the other. 

7.- — After a long rest period the subject is found to be in a 
condition to improve very rapidly. In some cases the results show 
that they have actually gained power during the rest period. 



BIBLIOGRAPHY 
Bair, J. H. — "Development of Voluntary Control." Psy. Rev., 

vol. 8, pp. 474-510- 

'The Practice Curve." Mon. Sup. No. 19 Psy. Rev. 
Book, W. F. — "The Psychology of Skill : with Special Reference 

to Its Acquisition in Typewriting." Univ. of Montana Pub- 
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Physiology of the Telegraphic Language." Psy. Rev., vol. 

4, pp. 27-53, and vol. 6, pp. 345-375- 
Johnson, W. S. — "Researches in Practice and Habit." Studies 

from the Yale Psychological Laboratory, vol, 6, pp. 51-103. 
Partridge, G. £.■ — "Experiments upon the Control of the Reflex 

Wink." Amer, Jour, of Psy., vol. 11, pp. 244-250. 
Scripture, E. W., Smith, T. L., and Brown, E. M. — "On the 

Education of Muscular Control and Power," Studies from 

the Yale Psychological Laboratory, vol. 2, pp. 11 4- 119, 
Shepard, John F, and Breed, F, S. — "Maturation and Use in the 

Development of an Instinct." Jour, of Animal Behavior, 

July- August, 191 3, vol. 3, no. 4, pp. 274-283. 
Starch, D. — "A Demonstration of the Trial and Error Method 

of Learning." Psy. Bui., vol. 7, pp. 20-23. 
Swift, E. J. — "Studies in the Psychology and Physiology of 

Learning." Amer. Jour, of Psy., vol. 14, pp. 201-251. 

"The Acquisition of Skill in Typewriting; A Contribution 

to the Psychology of Learning." Psy. Bui., vol I, pp. 295- 

305- 

"Memory of a Complex Skillful Act." Amer. Jour, of Psy. 

vol. 16, pp. 131-133. 

"Beginning a Language : A Contribution to the Psychology 

of Learning." Studies of Philosophy and Psychology by 

Former Students of Charles Edward Garman, pp. 297-313. 

"Memory of Skillful Movements." Psy. Bui., vol. 3, pp. 

185-187. 

"Relearning a skillful Act: An Experimental Study in 

Neuro-Muscular Memory." Psy. Bui., vol. 7, pp. 17-19. 

"Learning to Telegraph." Psy. Bui., vol. 7, pp. 149-153, 
Swift, E. J. and Schuyler, W. — "The Learning Process." Psy, 

Bui., vol. 4, pp. 307-310. 
Thorndike, E. L. — "Educational Psychology." Vol. 11, 
Wells, F, L. — Normal Performance in the Tapping Test." 

Amer. Jour, of Psy., vol. 19, pp. 437-483. 

"The Relation of Practice to Individual Differences." Amer. 

Jour, of Psy,, vol, 2^, pp, 75-88. 
Whitley, M. T. — "An Empirical Study of Certain Tests for In- 
dividual Differences," Archives of Psychology, No, 19. 



CURVES AND PLATES 

Curves I to V (inclusive) Plate I 

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Curve XV Plate III 

Curves XVI and XVII Plate IV 

Curve XVIa Plate VIII 

Curves XVIII and XIX Plate V 

Curves XX and XXI Plate VI 

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